Add WebP library for API 16.

Add workarounds for missing MIME type information on API 16.
Use WebP for compressing images.
2026-04-19 06:24:34 +02:00 · 2021-05-24 15:09:19 +01:00 · 2021-05-24 14:56:50 +01:00 · 2021-05-21 12:43:50 +01:00 · 2021-05-21 12:43:19 +01:00 · 2021-05-19 10:47:08 +01:00
897 changed files with 35760 additions and 14677 deletions
@@ -18,6 +18,7 @@ local.properties

 # Android Studio
 .idea/*
+!.idea/inspectionProfiles/
 !.idea/runConfigurations/
 !.idea/codeStyleSettings.xml
 !.idea/codeStyles
@@ -1,29 +1,79 @@
 image: briar/ci-image-android:latest

 stages:
- test
- check_reproducibility
+  - test
+  - optional_tests
+  - check_reproducibility

-test:
-  stage: test
+workflow:
+  # when to create a CI pipeline
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+    - if: '$CI_COMMIT_BRANCH && $CI_OPEN_MERGE_REQUESTS'
+      when: never # avoids duplicate jobs for branch and MR
+    - if: '$CI_COMMIT_BRANCH'
+    - if: '$CI_COMMIT_TAG'
+
+.base-test:
  before_script:
    - set -e
    - export GRADLE_USER_HOME=$PWD/.gradle
-
  cache:
+    key: "$CI_COMMIT_REF_SLUG"
    paths:
      - .gradle/wrapper
      - .gradle/caches
-
-  script:
-    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom animalSnifferMain animalSnifferTest
-    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom check compileOfficialDebugAndroidTestSources compileScreenshotDebugAndroidTestSources
-
  after_script:
-    # these file change every time but should not be cached
+    # these file change every time and should not be cached
    - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
    - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/

+test:
+  extends: .base-test
+  stage: test
+  script:
+    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom animalSnifferMain animalSnifferTest
+    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom check
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+      when: always
+    - when: always
+
+android test:
+  extends: .base-test
+  stage: optional_tests
+  image: briar/ci-image-android-emulator:latest
+  script:
+    # start emulator first, so it can fail early
+    - start-emulator.sh
+    # run normal and screenshot tests together (exclude Large tests)
+    - ./gradlew -Djava.security.egd=file:/dev/urandom connectedAndroidTest -Pandroid.testInstrumentationRunnerArguments.package=org.briarproject.briar.android -Pandroid.testInstrumentationRunnerArguments.notAnnotation=androidx.test.filters.LargeTest
+  after_script:
+    - adb pull /sdcard/Pictures/screenshots
+  artifacts:
+    name: "${CI_PROJECT_PATH}_${CI_JOB_STAGE}_${CI_COMMIT_REF_NAME}_${CI_COMMIT_SHA}"
+    paths:
+      - kernel.log
+      - logcat.txt
+      - briar-android/build/reports/androidTests/connected/flavors/*
+      - screenshots
+    expire_in: 3 days
+    when: on_failure
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+      when: on_success
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+      changes:
+        - briar-android/**/*
+      when: manual
+      allow_failure: true
+    - if: '$CI_COMMIT_TAG == null'
+      when: manual
+      allow_failure: true
+  retry:
+    max: 1
+  tags:
+    - kvm

 test_reproducible:
  stage: check_reproducibility
@@ -31,3 +81,38 @@ test_reproducible:
    - "curl -X POST -F token=${RELEASE_CHECK_TOKEN} -F ref=master -F variables[RELEASE_TAG]=${CI_COMMIT_REF_NAME} https://code.briarproject.org/api/v4/projects/61/trigger/pipeline"
  only:
    - tags
+
+.optional_tests:
+  stage: optional_tests
+  before_script:
+    - set -e
+    - export GRADLE_USER_HOME=$PWD/.gradle
+
+  cache:
+    key: "$CI_COMMIT_REF_SLUG"
+    paths:
+      - .gradle/wrapper
+      - .gradle/caches
+
+  script:
+    - OPTIONAL_TESTS=org.briarproject.bramble.plugin.tor.BridgeTest ./gradlew --info bramble-java:test --tests BridgeTest
+
+  after_script:
+    # these file change every time but should not be cached
+    - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
+    - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/
+
+bridge test:
+  extends: .optional_tests
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+      when: on_success
+      allow_failure: true
+    - if: '$CI_COMMIT_TAG == null'
+      when: manual
+      allow_failure: true
+
+pre_release_tests:
+  extends: .optional_tests
+  only:
+    - tags
@@ -28,6 +28,20 @@
      <option name="JD_ALIGN_EXCEPTION_COMMENTS" value="false" />
    </JavaCodeStyleSettings>
    <JetCodeStyleSettings>
+      <option name="PACKAGES_TO_USE_STAR_IMPORTS">
+        <value />
+      </option>
+      <option name="PACKAGES_IMPORT_LAYOUT">
+        <value>
+          <package name="" alias="false" withSubpackages="true" />
+          <package name="java" alias="false" withSubpackages="true" />
+          <package name="javax" alias="false" withSubpackages="true" />
+          <package name="kotlin" alias="false" withSubpackages="true" />
+          <package name="" alias="true" withSubpackages="true" />
+        </value>
+      </option>
+      <option name="NAME_COUNT_TO_USE_STAR_IMPORT" value="2147483647" />
+      <option name="NAME_COUNT_TO_USE_STAR_IMPORT_FOR_MEMBERS" value="2147483647" />
      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
    </JetCodeStyleSettings>
    <XML>
@@ -0,0 +1,15 @@
+<component name="ProjectDictionaryState">
+  <dictionary name="briar">
+    <words>
+      <w>briar</w>
+      <w>briarproject</w>
+      <w>emoji</w>
+      <w>encrypter</w>
+      <w>identicon</w>
+      <w>introducee</w>
+      <w>introducees</w>
+      <w>introducer</w>
+      <w>onboarding</w>
+    </words>
+  </dictionary>
+</component>
@@ -0,0 +1,14 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="MissingOverrideAnnotation" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="ignoreObjectMethods" value="true" />
+      <option name="ignoreAnonymousClassMethods" value="false" />
+    </inspection_tool>
+    <inspection_tool class="WeakerAccess" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="SUGGEST_PACKAGE_LOCAL_FOR_MEMBERS" value="true" />
+      <option name="SUGGEST_PACKAGE_LOCAL_FOR_TOP_CLASSES" value="true" />
+      <option name="SUGGEST_PRIVATE_FOR_INNERS" value="true" />
+    </inspection_tool>
+  </profile>
+</component>
@@ -1,6 +1,6 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="briar-android" />
+    <module name="briar.briar-android" />
    <option name="PACKAGE_NAME" value="" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
@@ -13,6 +13,7 @@
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-core" run_configuration_type="AndroidJUnit" />
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-android" run_configuration_type="AndroidJUnit" />
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-java" run_configuration_type="AndroidJUnit" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-api" run_configuration_type="AndroidJUnit" />
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-core" run_configuration_type="AndroidJUnit" />
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-headless" run_configuration_type="AndroidJUnit" />
    </method>
@@ -1,20 +1,14 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in bramble-android" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="bramble-android" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.bramble-android" />
    <option name="PACKAGE_NAME" value="" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
    <option name="TEST_OBJECT" value="package" />
-    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-android" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -1,20 +1,14 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in bramble-api" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="bramble-api" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.bramble-api" />
    <option name="PACKAGE_NAME" value="" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
    <option name="TEST_OBJECT" value="package" />
-    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-api" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -1,20 +1,14 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in bramble-core" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="bramble-core" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.bramble-core" />
    <option name="PACKAGE_NAME" value="" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
    <option name="TEST_OBJECT" value="package" />
-    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-core" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -1,8 +1,6 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in bramble-java" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="bramble-java" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.bramble-java" />
    <option name="PACKAGE_NAME" value="" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
@@ -10,11 +8,8 @@
    <option name="VM_PARAMETERS" value="-ea -Djava.library.path=libs" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-java" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -1,20 +1,14 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in briar-android" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="briar-android" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.briar-android" />
    <option name="PACKAGE_NAME" value="" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
    <option name="TEST_OBJECT" value="package" />
-    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-android" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -0,0 +1,14 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in briar-api" type="AndroidJUnit" factoryName="Android JUnit">
+    <module name="briar.briar-api" />
+    <option name="PACKAGE_NAME" value="" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-api" />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>
@@ -1,20 +1,14 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in briar-core" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="briar-core" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.briar-core" />
    <option name="PACKAGE_NAME" value="" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
    <option name="TEST_OBJECT" value="package" />
-    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-core" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -1,6 +1,6 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in briar-headless" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="briar-headless" />
+    <module name="briar.briar-headless" />
    <option name="PACKAGE_NAME" value="org.briarproject.briar.headless" />
    <option name="MAIN_CLASS_NAME" value="" />
    <option name="METHOD_NAME" value="" />
@@ -0,0 +1,24 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="BridgeTest" type="AndroidJUnit" factoryName="Android JUnit" nameIsGenerated="true">
+    <module name="briar.bramble-java" />
+    <useClassPathOnly />
+    <extension name="coverage">
+      <pattern>
+        <option name="PATTERN" value="org.briarproject.bramble.plugin.tor.*" />
+        <option name="ENABLED" value="true" />
+      </pattern>
+    </extension>
+    <option name="PACKAGE_NAME" value="org.briarproject.bramble.plugin.tor" />
+    <option name="MAIN_CLASS_NAME" value="org.briarproject.bramble.plugin.tor.BridgeTest" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="class" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="$MODULE_DIR$" />
+    <envs>
+      <env name="OPTIONAL_TESTS" value="org.briarproject.bramble.plugin.tor.BridgeTest" />
+    </envs>
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>
@@ -1,20 +1,14 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="H2 Performance Test" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="bramble-core" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.bramble-core" />
    <option name="PACKAGE_NAME" value="org.briarproject.bramble.db" />
    <option name="MAIN_CLASS_NAME" value="org.briarproject.bramble.db.H2DatabasePerformanceTest" />
    <option name="METHOD_NAME" value="" />
    <option name="TEST_OBJECT" value="class" />
-    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -1,20 +1,14 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="HyperSQL Performance Test" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="bramble-core" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
+    <module name="briar.bramble-core" />
    <option name="PACKAGE_NAME" value="org.briarproject.bramble.db" />
    <option name="MAIN_CLASS_NAME" value="org.briarproject.bramble.db.HyperSqlDatabasePerformanceTest" />
    <option name="METHOD_NAME" value="" />
    <option name="TEST_OBJECT" value="class" />
-    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <patterns />
-    <method />
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
  </configuration>
 </component>
@@ -0,0 +1,51 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Instrumentation Tests (destroys DB)" type="AndroidTestRunConfigurationType" factoryName="Android Instrumented Tests">
+    <module name="briar.briar-android" />
+    <option name="TESTING_TYPE" value="1" />
+    <option name="METHOD_NAME" value="" />
+    <option name="CLASS_NAME" value="" />
+    <option name="PACKAGE_NAME" value="org.briarproject.briar.android" />
+    <option name="INSTRUMENTATION_RUNNER_CLASS" value="" />
+    <option name="EXTRA_OPTIONS" value="-e notAnnotation androidx.test.filters.LargeTest" />
+    <option name="INCLUDE_GRADLE_EXTRA_OPTIONS" value="true" />
+    <option name="CLEAR_LOGCAT" value="false" />
+    <option name="SHOW_LOGCAT_AUTOMATICALLY" value="false" />
+    <option name="SKIP_NOOP_APK_INSTALLATIONS" value="true" />
+    <option name="FORCE_STOP_RUNNING_APP" value="true" />
+    <option name="TARGET_SELECTION_MODE" value="DEVICE_AND_SNAPSHOT_COMBO_BOX" />
+    <option name="DEBUGGER_TYPE" value="Auto" />
+    <Auto>
+      <option name="USE_JAVA_AWARE_DEBUGGER" value="false" />
+      <option name="SHOW_STATIC_VARS" value="true" />
+      <option name="WORKING_DIR" value="" />
+      <option name="TARGET_LOGGING_CHANNELS" value="lldb process:gdb-remote packets" />
+      <option name="SHOW_OPTIMIZED_WARNING" value="true" />
+    </Auto>
+    <Hybrid>
+      <option name="USE_JAVA_AWARE_DEBUGGER" value="false" />
+      <option name="SHOW_STATIC_VARS" value="true" />
+      <option name="WORKING_DIR" value="" />
+      <option name="TARGET_LOGGING_CHANNELS" value="lldb process:gdb-remote packets" />
+      <option name="SHOW_OPTIMIZED_WARNING" value="true" />
+    </Hybrid>
+    <Java />
+    <Native>
+      <option name="USE_JAVA_AWARE_DEBUGGER" value="false" />
+      <option name="SHOW_STATIC_VARS" value="true" />
+      <option name="WORKING_DIR" value="" />
+      <option name="TARGET_LOGGING_CHANNELS" value="lldb process:gdb-remote packets" />
+      <option name="SHOW_OPTIMIZED_WARNING" value="true" />
+    </Native>
+    <Profilers>
+      <option name="ADVANCED_PROFILING_ENABLED" value="false" />
+      <option name="STARTUP_PROFILING_ENABLED" value="false" />
+      <option name="STARTUP_CPU_PROFILING_ENABLED" value="false" />
+      <option name="STARTUP_CPU_PROFILING_CONFIGURATION_NAME" value="Sample Java Methods" />
+      <option name="STARTUP_NATIVE_MEMORY_PROFILING_ENABLED" value="false" />
+      <option name="NATIVE_MEMORY_SAMPLE_RATE_BYTES" value="2048" />
+    </Profilers>
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>
@@ -1,6 +1,6 @@
 <component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="briar-headless" type="JetRunConfigurationType" factoryName="Kotlin" singleton="true">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+  <configuration default="false" name="briar-headless" type="JetRunConfigurationType" singleton="true">
+    <module name="briar.briar-headless" />
    <option name="VM_PARAMETERS" value="" />
    <option name="PROGRAM_PARAMETERS" value="-v" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
@@ -8,9 +8,8 @@
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="MAIN_CLASS_NAME" value="org.briarproject.briar.headless.MainKt" />
    <option name="WORKING_DIRECTORY" value="" />
-    <module name="briar-headless" />
-    <envs />
-    <method>
+    <method v="2">
+      <option name="Make" enabled="true" />
      <option name="Gradle.BeforeRunTask" enabled="true" tasks="jar" externalProjectPath="$PROJECT_DIR$/briar-headless" vmOptions="" scriptParameters="" />
    </method>
  </configuration>
@@ -3,3 +3,4 @@ gen
 build
 .settings
 src/main/res/raw/*.zip
+src/main/jniLibs
@@ -5,14 +5,18 @@ apply plugin: 'witness'
 apply from: 'witness.gradle'

 android {
-	compileSdkVersion 29
-	buildToolsVersion '29.0.2'
+	compileSdkVersion 30
+	buildToolsVersion '30.0.3'
+
+	packagingOptions {
+		doNotStrip '**/*.so'
+	}

 	defaultConfig {
 		minSdkVersion 16
-		targetSdkVersion 28
-		versionCode 10209
-		versionName "1.2.9"
+		targetSdkVersion 30
+		versionCode 10304
+		versionName "1.3.4"
 		consumerProguardFiles 'proguard-rules.txt'

 		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -38,8 +42,8 @@ configurations {

 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.5.10@zip'
-	tor 'org.briarproject:obfs4proxy-android:0.0.11-2@zip'
+	tor 'org.briarproject:tor-android:0.3.5.13@zip'
+	tor 'org.briarproject:obfs4proxy-android:0.0.12-dev-40245c4a@zip'

 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'

@@ -53,10 +57,12 @@ dependencies {
 }

 def torBinariesDir = 'src/main/res/raw'
+def torLibsDir = 'src/main/jniLibs'

 task cleanTorBinaries {
 	doLast {
 		delete fileTree(torBinariesDir) { include '*.zip' }
+		delete fileTree(torLibsDir) { include '**/*.so' }
 	}
 }

@@ -67,8 +73,36 @@ task unpackTorBinaries {
 		copy {
 			from configurations.tor.collect { zipTree(it) }
 			into torBinariesDir
-			// TODO: Remove after next Tor upgrade, which won't include non-PIE binaries
-			include 'geoip.zip', '*_pie.zip'
+			include 'geoip.zip'
+		}
+		configurations.tor.each { outer ->
+			zipTree(outer).each { inner ->
+				if (inner.name.endsWith('_arm_pie.zip')) {
+					copy {
+						from zipTree(inner)
+						into torLibsDir
+						rename '(.*)', 'armeabi-v7a/lib$1.so'
+					}
+				} else if (inner.name.endsWith('_arm64_pie.zip')) {
+					copy {
+						from zipTree(inner)
+						into torLibsDir
+						rename '(.*)', 'arm64-v8a/lib$1.so'
+					}
+				} else if (inner.name.endsWith('_x86_pie.zip')) {
+					copy {
+						from zipTree(inner)
+						into torLibsDir
+						rename '(.*)', 'x86/lib$1.so'
+					}
+				} else if (inner.name.endsWith('_x86_64_pie.zip')) {
+					copy {
+						from zipTree(inner)
+						into torLibsDir
+						rename '(.*)', 'x86_64/lib$1.so'
+					}
+				}
+			}
 		}
 	}
 	dependsOn cleanTorBinaries
@@ -76,5 +110,6 @@ task unpackTorBinaries {

 tasks.withType(MergeResources) {
 	inputs.dir torBinariesDir
+	inputs.dir torLibsDir
 	dependsOn unpackTorBinaries
 }
@@ -1,11 +1,15 @@
 package org.briarproject.bramble.network;

+import android.annotation.TargetApi;
 import android.app.Application;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.net.ConnectivityManager;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
 import android.net.NetworkInfo;

 import org.briarproject.bramble.api.event.EventBus;
@@ -19,6 +23,11 @@ import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.system.TaskScheduler;
 import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;

+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.Enumeration;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -36,16 +45,22 @@ import static android.net.ConnectivityManager.TYPE_WIFI;
 import static android.net.wifi.p2p.WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
+import static java.net.NetworkInterface.getNetworkInterfaces;
+import static java.util.Collections.list;
 import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
+import static org.briarproject.bramble.util.LogUtils.logException;

@MethodsNotNullByDefault
@ParametersNotNullByDefault
 class AndroidNetworkManager implements NetworkManager, Service {

 	private static final Logger LOG =
-			Logger.getLogger(AndroidNetworkManager.class.getName());
+			getLogger(AndroidNetworkManager.class.getName());

 	// See android.net.wifi.WifiManager
 	private static final String WIFI_AP_STATE_CHANGED_ACTION =
@@ -54,7 +69,8 @@ class AndroidNetworkManager implements NetworkManager, Service {
 	private final TaskScheduler scheduler;
 	private final EventBus eventBus;
 	private final Executor eventExecutor;
-	private final Context appContext;
+	private final Application app;
+	private final ConnectivityManager connectivityManager;
 	private final AtomicReference<Cancellable> connectivityCheck =
 			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
@@ -67,7 +83,9 @@ class AndroidNetworkManager implements NetworkManager, Service {
 		this.scheduler = scheduler;
 		this.eventBus = eventBus;
 		this.eventExecutor = eventExecutor;
-		this.appContext = app.getApplicationContext();
+		this.app = app;
+		connectivityManager = (ConnectivityManager)
+				requireNonNull(app.getSystemService(CONNECTIVITY_SERVICE));
 	}

 	@Override
@@ -82,24 +100,82 @@ class AndroidNetworkManager implements NetworkManager, Service {
 		filter.addAction(WIFI_AP_STATE_CHANGED_ACTION);
 		filter.addAction(WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
 		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
-		appContext.registerReceiver(networkStateReceiver, filter);
+		app.registerReceiver(networkStateReceiver, filter);
 	}

 	@Override
 	public void stopService() {
 		if (networkStateReceiver != null)
-			appContext.unregisterReceiver(networkStateReceiver);
+			app.unregisterReceiver(networkStateReceiver);
 	}

 	@Override
 	public NetworkStatus getNetworkStatus() {
-		ConnectivityManager cm = (ConnectivityManager)
-				appContext.getSystemService(CONNECTIVITY_SERVICE);
-		if (cm == null) throw new AssertionError();
-		NetworkInfo net = cm.getActiveNetworkInfo();
+		NetworkInfo net = connectivityManager.getActiveNetworkInfo();
 		boolean connected = net != null && net.isConnected();
-		boolean wifi = connected && net.getType() == TYPE_WIFI;
-		return new NetworkStatus(connected, wifi);
+		boolean wifi = false, ipv6Only = false;
+		if (connected) {
+			wifi = net.getType() == TYPE_WIFI;
+			if (SDK_INT >= 23) ipv6Only = isActiveNetworkIpv6Only();
+			else ipv6Only = areAllAvailableNetworksIpv6Only();
+		}
+		return new NetworkStatus(connected, wifi, ipv6Only);
+	}
+
+	/**
+	 * Returns true if the
+	 * {@link ConnectivityManager#getActiveNetwork() active network} has an
+	 * IPv6 unicast address and no IPv4 addresses. The active network is
+	 * assumed not to be a loopback interface.
+	 */
+	@TargetApi(23)
+	private boolean isActiveNetworkIpv6Only() {
+		Network net = connectivityManager.getActiveNetwork();
+		if (net == null) {
+			LOG.info("No active network");
+			return false;
+		}
+		LinkProperties props = connectivityManager.getLinkProperties(net);
+		if (props == null) {
+			LOG.info("No link properties for active network");
+			return false;
+		}
+		boolean hasIpv6Unicast = false;
+		for (LinkAddress linkAddress : props.getLinkAddresses()) {
+			InetAddress addr = linkAddress.getAddress();
+			if (addr instanceof Inet4Address) return false;
+			if (!addr.isMulticastAddress()) hasIpv6Unicast = true;
+		}
+		return hasIpv6Unicast;
+	}
+
+	/**
+	 * Returns true if the device has at least one network interface with an
+	 * IPv6 unicast address and no interfaces with IPv4 addresses, excluding
+	 * loopback interfaces and interfaces that are
+	 * {@link NetworkInterface#isUp() down}. If this method returns true and
+	 * the device has internet access then it's via IPv6 only.
+	 */
+	private boolean areAllAvailableNetworksIpv6Only() {
+		try {
+			Enumeration<NetworkInterface> interfaces = getNetworkInterfaces();
+			if (interfaces == null) {
+				LOG.info("No network interfaces");
+				return false;
+			}
+			boolean hasIpv6Unicast = false;
+			for (NetworkInterface i : list(interfaces)) {
+				if (i.isLoopback() || !i.isUp()) continue;
+				for (InetAddress addr : list(i.getInetAddresses())) {
+					if (addr instanceof Inet4Address) return false;
+					if (!addr.isMulticastAddress()) hasIpv6Unicast = true;
+				}
+			}
+			return hasIpv6Unicast;
+		} catch (SocketException e) {
+			logException(LOG, WARNING, e);
+			return false;
+		}
 	}

 	private void updateConnectionStatus() {
@@ -59,8 +59,8 @@ import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;

@MethodsNotNullByDefault
@ParametersNotNullByDefault
-class AndroidBluetoothPlugin
-		extends BluetoothPlugin<BluetoothSocket, BluetoothServerSocket> {
+class AndroidBluetoothPlugin extends
+		AbstractBluetoothPlugin<BluetoothSocket, BluetoothServerSocket> {

 	private static final Logger LOG =
 			getLogger(AndroidBluetoothPlugin.class.getName());
@@ -71,11 +71,11 @@ class AndroidBluetoothPlugin
 	private final Application app;
 	private final Clock clock;

-	private volatile boolean wasEnabledByUs = false;
 	private volatile BluetoothStateReceiver receiver = null;

 	// Non-null if the plugin started successfully
 	private volatile BluetoothAdapter adapter = null;
+	private volatile boolean stopDiscoverAndConnect;

 	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
 			BluetoothConnectionFactory<BluetoothSocket> connectionFactory,
@@ -133,41 +133,10 @@ class AndroidBluetoothPlugin
 		return adapter != null && adapter.isEnabled();
 	}

-	@Override
-	void enableAdapter() {
-		if (adapter != null && !adapter.isEnabled()) {
-			if (adapter.enable()) {
-				LOG.info("Enabling Bluetooth");
-				wasEnabledByUs = true;
-			} else {
-				LOG.info("Could not enable Bluetooth");
-			}
-		}
-	}
-
-	@Override
-	void disableAdapterIfEnabledByUs() {
-		if (isAdapterEnabled() && wasEnabledByUs) {
-			if (adapter.disable()) LOG.info("Disabling Bluetooth");
-			else LOG.info("Could not disable Bluetooth");
-			wasEnabledByUs = false;
-		}
-	}
-
-	@Override
-	void setEnabledByUs() {
-		wasEnabledByUs = true;
-	}
-
-	@Override
-	void onAdapterDisabled() {
-		super.onAdapterDisabled();
-		wasEnabledByUs = false;
-	}
-
 	@Override
 	@Nullable
 	String getBluetoothAddress() {
+		if (adapter == null) return null;
 		String address = AndroidUtils.getBluetoothAddress(app, adapter);
 		return address.isEmpty() ? null : address;
 	}
@@ -207,6 +176,11 @@ class AndroidBluetoothPlugin
 		} catch (IOException e) {
 			IoUtils.tryToClose(s, LOG, WARNING);
 			throw e;
+		} catch (NullPointerException e) {
+			// BluetoothSocket#connect() may throw an NPE under unknown
+			// circumstances
+			IoUtils.tryToClose(s, LOG, WARNING);
+			throw new IOException(e);
 		}
 	}

@@ -214,22 +188,40 @@ class AndroidBluetoothPlugin
 	@Nullable
 	DuplexTransportConnection discoverAndConnect(String uuid) {
 		if (adapter == null) return null;
-		for (String address : discoverDevices()) {
-			try {
-				if (LOG.isLoggable(INFO))
-					LOG.info("Connecting to " + scrubMacAddress(address));
-				return connectTo(address, uuid);
-			} catch (IOException e) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Could not connect to "
-							+ scrubMacAddress(address));
+		if (!discoverSemaphore.tryAcquire()) {
+			LOG.info("Discover already running");
+			return null;
+		}
+		try {
+			stopDiscoverAndConnect = false;
+			for (String address : discoverDevices()) {
+				if (stopDiscoverAndConnect) {
+					break;
+				}
+				try {
+					if (LOG.isLoggable(INFO))
+						LOG.info("Connecting to " + scrubMacAddress(address));
+					return connectTo(address, uuid);
+				} catch (IOException e) {
+					if (LOG.isLoggable(INFO)) {
+						LOG.info("Could not connect to "
+								+ scrubMacAddress(address));
+					}
 				}
 			}
+		} finally {
+			discoverSemaphore.release();
 		}
 		LOG.info("Could not connect to any devices");
 		return null;
 	}

+	@Override
+	public void stopDiscoverAndConnect() {
+		stopDiscoverAndConnect = true;
+		adapter.cancelDiscovery();
+	}
+
 	private Collection<String> discoverDevices() {
 		List<String> addresses = new ArrayList<>();
 		BlockingQueue<Intent> intents = new LinkedBlockingQueue<>();
@@ -16,19 +16,42 @@ import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.api.system.ResourceProvider;
+import org.briarproject.bramble.util.AndroidUtils;

 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;

 import javax.net.SocketFactory;

+import static android.os.Build.VERSION.SDK_INT;
+import static java.util.Arrays.asList;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+
@MethodsNotNullByDefault
@ParametersNotNullByDefault
 class AndroidTorPlugin extends TorPlugin {

+	private static final List<String> LIBRARY_ARCHITECTURES =
+			asList("armeabi-v7a", "arm64-v8a", "x86", "x86_64");
+
+	private static final String TOR_LIB_NAME = "libtor.so";
+	private static final String OBFS4_LIB_NAME = "libobfs4proxy.so";
+
+	private static final Logger LOG =
+			getLogger(AndroidTorPlugin.class.getName());
+
 	private final Application app;
 	private final AndroidWakeLock wakeLock;
+	private final File torLib, obfs4Lib;

 	AndroidTorPlugin(Executor ioExecutor,
 			Executor wakefulIoExecutor,
@@ -55,6 +78,9 @@ class AndroidTorPlugin extends TorPlugin {
 				maxIdleTime, torDirectory);
 		this.app = app;
 		wakeLock = wakeLockManager.createWakeLock("TorPlugin");
+		String nativeLibDir = app.getApplicationInfo().nativeLibraryDir;
+		torLib = new File(nativeLibDir, TOR_LIB_NAME);
+		obfs4Lib = new File(nativeLibDir, OBFS4_LIB_NAME);
 	}

 	@Override
@@ -85,4 +111,112 @@ class AndroidTorPlugin extends TorPlugin {
 		super.stop();
 		wakeLock.release();
 	}
+
+	@Override
+	protected File getTorExecutableFile() {
+		return torLib.exists() ? torLib : super.getTorExecutableFile();
+	}
+
+	@Override
+	protected File getObfs4ExecutableFile() {
+		return obfs4Lib.exists() ? obfs4Lib : super.getObfs4ExecutableFile();
+	}
+
+	@Override
+	protected void installTorExecutable() throws IOException {
+		File extracted = super.getTorExecutableFile();
+		if (torLib.exists()) {
+			// If an older version left behind a Tor binary, delete it
+			if (extracted.exists()) {
+				if (extracted.delete()) LOG.info("Deleted Tor binary");
+				else LOG.info("Failed to delete Tor binary");
+			}
+		} else if (SDK_INT < 29) {
+			// The binary wasn't extracted at install time. Try to extract it
+			extractLibraryFromApk(TOR_LIB_NAME, extracted);
+		} else {
+			// No point extracting the binary, we won't be allowed to execute it
+			throw new FileNotFoundException(torLib.getAbsolutePath());
+		}
+	}
+
+	@Override
+	protected void installObfs4Executable() throws IOException {
+		File extracted = super.getObfs4ExecutableFile();
+		if (obfs4Lib.exists()) {
+			// If an older version left behind an obfs4 binary, delete it
+			if (extracted.exists()) {
+				if (extracted.delete()) LOG.info("Deleted obfs4 binary");
+				else LOG.info("Failed to delete obfs4 binary");
+			}
+		} else if (SDK_INT < 29) {
+			// The binary wasn't extracted at install time. Try to extract it
+			extractLibraryFromApk(OBFS4_LIB_NAME, extracted);
+		} else {
+			// No point extracting the binary, we won't be allowed to execute it
+			throw new FileNotFoundException(obfs4Lib.getAbsolutePath());
+		}
+	}
+
+	private void extractLibraryFromApk(String libName, File dest)
+			throws IOException {
+		File sourceDir = new File(app.getApplicationInfo().sourceDir);
+		if (sourceDir.isFile()) {
+			// Look for other APK files in the same directory, if we're allowed
+			File parent = sourceDir.getParentFile();
+			if (parent != null) sourceDir = parent;
+		}
+		List<String> libPaths = getSupportedLibraryPaths(libName);
+		for (File apk : findApkFiles(sourceDir)) {
+			ZipInputStream zin = new ZipInputStream(new FileInputStream(apk));
+			for (ZipEntry e = zin.getNextEntry(); e != null;
+					e = zin.getNextEntry()) {
+				if (libPaths.contains(e.getName())) {
+					if (LOG.isLoggable(INFO)) {
+						LOG.info("Extracting " + e.getName()
+								+ " from " + apk.getAbsolutePath());
+					}
+					extract(zin, dest); // Zip input stream will be closed
+					return;
+				}
+			}
+			zin.close();
+		}
+		throw new FileNotFoundException(libName);
+	}
+
+	/**
+	 * Returns all files with the extension .apk or .APK under the given root.
+	 */
+	private List<File> findApkFiles(File root) {
+		List<File> files = new ArrayList<>();
+		findApkFiles(root, files);
+		return files;
+	}
+
+	private void findApkFiles(File f, List<File> files) {
+		if (f.isFile() && f.getName().toLowerCase().endsWith(".apk")) {
+			files.add(f);
+		} else if (f.isDirectory()) {
+			File[] children = f.listFiles();
+			if (children != null) {
+				for (File child : children) findApkFiles(child, files);
+			}
+		}
+	}
+
+	/**
+	 * Returns the paths at which libraries with the given name would be found
+	 * inside an APK file, for all architectures supported by the device, in
+	 * order of preference.
+	 */
+	private List<String> getSupportedLibraryPaths(String libName) {
+		List<String> architectures = new ArrayList<>();
+		for (String abi : AndroidUtils.getSupportedArchitectures()) {
+			if (LIBRARY_ARCHITECTURES.contains(abi)) {
+				architectures.add("lib/" + abi + "/" + libName);
+			}
+		}
+		return architectures;
+	}
 }
@@ -6,8 +6,6 @@ import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 import android.content.ContentResolver;
 import android.content.Context;
-import android.net.wifi.WifiConfiguration;
-import android.net.wifi.WifiManager;
 import android.os.Build;
 import android.os.Parcel;
 import android.os.StrictMode;
@@ -17,12 +15,10 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

 import java.io.DataOutputStream;
 import java.io.IOException;
-import java.util.List;

 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;

-import static android.content.Context.WIFI_SERVICE;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.provider.Settings.Secure.ANDROID_ID;

@@ -52,15 +48,6 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 		String id = Settings.Secure.getString(contentResolver, ANDROID_ID);
 		if (id != null) out.writeUTF(id);
 		Parcel parcel = Parcel.obtain();
-		WifiManager wm = (WifiManager) appContext.getApplicationContext()
-				.getSystemService(WIFI_SERVICE);
-		if (wm != null) {
-			List<WifiConfiguration> configs = wm.getConfiguredNetworks();
-			if (configs != null) {
-				for (WifiConfiguration config : configs)
-					parcel.writeParcelable(config, 0);
-			}
-		}
 		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
 		if (bt != null) {
 			for (BluetoothDevice device : bt.getBondedDevices())
@@ -2,7 +2,6 @@ package org.briarproject.bramble.system;

 import android.app.Application;
 import android.content.Context;
-import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.os.PowerManager;

@@ -106,14 +105,21 @@ class AndroidWakeLockManagerImpl implements AndroidWakeLockManager {

 	private String getWakeLockTag(Context ctx) {
 		PackageManager pm = ctx.getPackageManager();
-		for (PackageInfo info : pm.getInstalledPackages(0)) {
-			String name = info.packageName.toLowerCase();
-			if (name.startsWith("com.huawei.powergenie")) {
-				return "LocationManagerService";
-			} else if (name.startsWith("com.evenwell.powermonitor")) {
-				return "AudioIn";
-			}
+		if (isInstalled(pm, "com.huawei.powergenie")) {
+			return "LocationManagerService";
+		} else if (isInstalled(pm, "com.evenwell.PowerMonitor")) {
+			return "AudioIn";
 		}
 		return ctx.getPackageName();
 	}
+
+	private boolean isInstalled(PackageManager pm, String packageName) {
+		try {
+			pm.getPackageInfo(packageName, 0);
+			return true;
+		} catch (PackageManager.NameNotFoundException e) {
+			return false;
+		}
+	}
+
 }
@@ -10,17 +10,20 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

 import java.io.File;
+import java.io.IOException;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.Scanner;

 import javax.annotation.Nullable;

 import static android.content.Context.MODE_PRIVATE;
 import static android.os.Build.VERSION.SDK_INT;
+import static java.lang.Runtime.getRuntime;
 import static java.util.Arrays.asList;
 import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;

@@ -31,6 +34,7 @@ public class AndroidUtils {
 	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";

 	private static final String STORED_REPORTS = "dev-reports";
+	private static final String STORED_LOGCAT = "dev-logcat";

 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
@@ -107,14 +111,32 @@ public class AndroidUtils {
 		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
 	}

+	public static File getLogcatFile(Context ctx) {
+		return new File(ctx.getFilesDir(), STORED_LOGCAT);
+	}
+
 	/**
 	 * Returns an array of supported content types for image attachments.
-	 * GIFs can't be compressed on API < 24 so they're not supported.
-	 * <p>
-	 * TODO: Remove this restriction when large message support is added
 	 */
 	public static String[] getSupportedImageContentTypes() {
-		if (SDK_INT < 24) return new String[] {"image/jpeg", "image/png"};
-		else return new String[] {"image/jpeg", "image/png", "image/gif"};
+		return new String[] {
+				"image/jpeg",
+				"image/png",
+				"image/gif",
+				"image/webp"
+		};
+	}
+
+	@Nullable
+	public static String getSystemProperty(String propName) {
+		try {
+			Process p = getRuntime().exec("getprop " + propName);
+			Scanner s = new Scanner(p.getInputStream());
+			String line = s.nextLine();
+			s.close();
+			return line;
+		} catch (SecurityException | IOException e) {
+			return null;
+		}
 	}
 }
@@ -1,33 +1,36 @@
 dependencyVerification {
    verify = [
        'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-        'com.android.tools.analytics-library:protos:26.5.1:protos-26.5.1.jar:8dde1130725461fe827f2a343d353f2b51e8870661fc860d7d5ebddb097ead4e',
-        'com.android.tools.analytics-library:shared:26.5.1:shared-26.5.1.jar:ccc2f3b00ec17b11401610ba68553544fc8fc517120e84439ac6eb86b875e18d',
-        'com.android.tools.analytics-library:tracker:26.5.1:tracker-26.5.1.jar:3a76984c0fe2e847ca7a8b35b4780ef0447a9d1666946cb8e60466318e0ab5ae',
-        'com.android.tools.build:aapt2-proto:0.4.0:aapt2-proto-0.4.0.jar:fac0435e08898f89eeeb9ca236bea707155ff816c12205ced285ad53604133ca',
-        'com.android.tools.build:apksig:3.5.1:apksig-3.5.1.jar:1fd33e7f009a2a0da766cfeec4211a09f548034b015c289a66d75dd8a9302f4a',
-        'com.android.tools.build:apkzlib:3.5.1:apkzlib-3.5.1.jar:9f330167cbe973b7db407692f74f4f6453b7ffa5f2048934b06280c2ceee60fa',
-        'com.android.tools.build:builder-model:3.5.1:builder-model-3.5.1.jar:39ea3c82b76b6e0c9f9fa88d93e0edc1dd4a0f1dfae0ef6fbf2d451da47e5450',
-        'com.android.tools.build:builder-test-api:3.5.1:builder-test-api-3.5.1.jar:a1b59305584cbcaa078fdc9cfb80871012755b822dd32e8da19add6f7bbcb762',
-        'com.android.tools.build:builder:3.5.1:builder-3.5.1.jar:e3a8d382434c5f60990730c4719fc814e85a898a33a1e96c1df8d627d3c6eea6',
-        'com.android.tools.build:gradle-api:3.5.1:gradle-api-3.5.1.jar:be9b41859bace11998f66b04ed944f87e413f3ad6da3c4665587699da125addc',
-        'com.android.tools.build:manifest-merger:26.5.1:manifest-merger-26.5.1.jar:dcad9ecb967251f4d750f55a4204a2b400e8fbfe5cb930a1d0d5dbe10ae8bdfc',
-        'com.android.tools.ddms:ddmlib:26.5.1:ddmlib-26.5.1.jar:b081aef2a4ed3f4d47cae4cdb128469735f25a114e026d37123bf9ffdec742a8',
-        'com.android.tools.external.com-intellij:intellij-core:26.5.1:intellij-core-26.5.1.jar:20eced30adc124805bd93488d9cd9d3e33e6bf7b48e9fe5a703d4983f894d450',
-        'com.android.tools.external.com-intellij:kotlin-compiler:26.5.1:kotlin-compiler-26.5.1.jar:5aed762dd54875b77ae7018d97c05756ff0c5b9fd02ec595dd396ccd14cc22cb',
-        'com.android.tools.external.org-jetbrains:uast:26.5.1:uast-26.5.1.jar:4bc8653d6c0943f40fee963a149e36c6baa45683d2530968a13f5007e3c40740',
-        'com.android.tools.layoutlib:layoutlib-api:26.5.1:layoutlib-api-26.5.1.jar:88732f11396c427273e515d23042e35633f4fe4295528a99b866aa2adf0efd9c',
-        'com.android.tools.lint:lint-api:26.5.1:lint-api-26.5.1.jar:ec33fcd72bfaf70dd841e03fbfd93f109c2e575aec146067c606689c3972f0de',
-        'com.android.tools.lint:lint-checks:26.5.1:lint-checks-26.5.1.jar:a1b9607d484aaae7a71dcecdc76f8003d8239af226c776894a2cf63f9e6c60d7',
-        'com.android.tools.lint:lint-gradle-api:26.5.1:lint-gradle-api-26.5.1.jar:82453fd98a8394cc84ed995c04d2cd744abd1d6589403427ba7eef53115406f3',
-        'com.android.tools.lint:lint-gradle:26.5.1:lint-gradle-26.5.1.jar:59465b56cf7db77c656d5f8195d721c3d48b6bdd0502d774de335bfe4baff00b',
-        'com.android.tools.lint:lint:26.5.1:lint-26.5.1.jar:336e4b04ec6f8b0f25879131b7a7862d77df83a1879ee5b71be26128755f8e2e',
-        'com.android.tools:annotations:26.5.1:annotations-26.5.1.jar:2c43c82f8c59d8f7a61e3239e1a2dc9f69dc342ec09af9b7c9f69b25337c0b6e',
-        'com.android.tools:common:26.5.1:common-26.5.1.jar:eccfa54486ed54c4e3123cc42195d023bd0dd21bcd2f0e4868e8c6fc70f8ef6b',
-        'com.android.tools:dvlib:26.5.1:dvlib-26.5.1.jar:46f93ad498b4756e7d867d2fe38c38890a80e7407a4ae459e4a8c8d5c5aeacfe',
-        'com.android.tools:repository:26.5.1:repository-26.5.1.jar:2b3ee791aa4c3e8ce60498c161a27ca7228816fc630eed4d9f25f2f36a106dce',
-        'com.android.tools:sdk-common:26.5.1:sdk-common-26.5.1.jar:365f749676c3574676fd465177c8a492f340816db2b520d6ed114d3b6e77bea7',
-        'com.android.tools:sdklib:26.5.1:sdklib-26.5.1.jar:007da104afb27c8c682a1628023fe9ec438249c8d15ef0fd6624c5bb8e23b696',
+        'com.android.tools.analytics-library:protos:27.1.1:protos-27.1.1.jar:13f77e73762e58ab372d140b3a6be6903aea9775b62dd14fbc62d4cc7069c9a4',
+        'com.android.tools.analytics-library:shared:27.1.1:shared-27.1.1.jar:82930a52001410e97d809930b670f4de3002286975f046b9de5f6b777b06d366',
+        'com.android.tools.analytics-library:tracker:27.1.1:tracker-27.1.1.jar:31bc5a00be0055bac89c9b2f34751883e987cd89e3ac1783720645c164f591d9',
+        'com.android.tools.build:aapt2-proto:4.1.0-alpha01-6193524:aapt2-proto-4.1.0-alpha01-6193524.jar:17e75523e1e92dd4f222c7368ee41df9e964a508232f591e265d0c499baf9dca',
+        'com.android.tools.build:apksig:4.1.1:apksig-4.1.1.jar:e0a69da9e5a03986d608b45bbf954ef0e6a0b3f58c1b8315bd169ec08b279e72',
+        'com.android.tools.build:apkzlib:4.1.1:apkzlib-4.1.1.jar:ba4b5e419b6be0130eae7f8301c3a551ad3976f487d2e0c6852ebb175ac41127',
+        'com.android.tools.build:builder-model:4.1.1:builder-model-4.1.1.jar:e95c99cc298ad67b8deb6ced99c51abc8f59afebedad044b1a10dde14646a4dd',
+        'com.android.tools.build:builder-test-api:4.1.1:builder-test-api-4.1.1.jar:464f596ab261c051c3847406748e843770dea123f6fa5fee8a9390644e709b7a',
+        'com.android.tools.build:builder:4.1.1:builder-4.1.1.jar:0f78d4759d2f7b57b95865522ec34596ba419b9982f3b25e3449213f9c98b80d',
+        'com.android.tools.build:gradle-api:4.1.1:gradle-api-4.1.1.jar:d42e6b539e4c1353ad3546e75ec8ce11a017b97481023e8ea18577eefe374358',
+        'com.android.tools.build:manifest-merger:27.1.1:manifest-merger-27.1.1.jar:7a45fa143687859bb2e5a961dcf6ee88094d3853de0cb543dc03dbcb0f4b554b',
+        'com.android.tools.ddms:ddmlib:27.1.1:ddmlib-27.1.1.jar:da6e4bd834b6a85dae8019039849d8bd96933347dfbf460df74913ddade6e40a',
+        'com.android.tools.external.com-intellij:intellij-core:27.1.1:intellij-core-27.1.1.jar:2591a7363c4443c59bf9f793730acafce9d6ec3076e2f46716edaf53a41b6fb6',
+        'com.android.tools.external.com-intellij:kotlin-compiler:27.1.1:kotlin-compiler-27.1.1.jar:5054ae770ba788f110303c65abd6b1fa28eccf52dee1274510e201b2b81885c8',
+        'com.android.tools.external.org-jetbrains:uast:27.1.1:uast-27.1.1.jar:54cd8f6886a9d2f5641659dd5c91f626629672cd48301f7f0bd6aad9bd448714',
+        'com.android.tools.layoutlib:layoutlib-api:27.1.1:layoutlib-api-27.1.1.jar:8a9a22e3b309521ea83b724e5a89cfdac6076f52d675c0e17d77b05527bc0f8c',
+        'com.android.tools.lint:lint-api:27.1.1:lint-api-27.1.1.jar:c1d8176094cb0478786070d40533efb578ebc53529a82f6ef5bee879bdca418b',
+        'com.android.tools.lint:lint-checks:27.1.1:lint-checks-27.1.1.jar:3899c91e00bd059b40c31a9ca00cd0f8303191947608735ae1b657323693fb61',
+        'com.android.tools.lint:lint-gradle-api:27.1.1:lint-gradle-api-27.1.1.jar:26aa89d38b9825cc73229daa82a68875801c8b8491f30497ce62aff1f206eb0d',
+        'com.android.tools.lint:lint-gradle:27.1.1:lint-gradle-27.1.1.jar:f7355823ead869f4d28184ba28b7a0c693b507519a2d3705bb9848a0f35b3756',
+        'com.android.tools.lint:lint-model:27.1.1:lint-model-27.1.1.jar:bc23c0c413bdfca59dac2cd56b870d8360d009e9ec0d365e71f774bcf127971d',
+        'com.android.tools.lint:lint:27.1.1:lint-27.1.1.jar:2f6038a5398a42bd591883c3f5e5894f4ec52ca1c3683bf94fa8553c1700af81',
+        'com.android.tools:annotations:27.1.1:annotations-27.1.1.jar:ff28c504d2acb9fd1a5ffbd97ae85cf59ee18c76927525aad250509bccf2cab1',
+        'com.android.tools:common:27.1.1:common-27.1.1.jar:63d9a2a9ad6d278db319f3749b9f50bdf5457ef7020074a1bebe124e714b535c',
+        'com.android.tools:dvlib:27.1.1:dvlib-27.1.1.jar:998a54201fc1cefee5f2399215e95c42b1f64f9e1d8f4452eb8255c68ba5440f',
+        'com.android.tools:repository:27.1.1:repository-27.1.1.jar:d25b74ccabf4d876903efb375e9af6fb380d8ae0445bb74bbdcc225c1e37fa1d',
+        'com.android.tools:sdk-common:27.1.1:sdk-common-27.1.1.jar:4473ae97d0ef7061ee1de61041d5aa97405ae08e44c09cf7bb278b42e4b97c7c',
+        'com.android.tools:sdklib:27.1.1:sdklib-27.1.1.jar:08e6b83961ac9724b3c1e3d0eff971f13be6701292c77914b8794480f3391250',
+        'com.android:signflinger:4.1.1:signflinger-4.1.1.jar:0c66825988873ec2d51057fa463f54a8f18fc7326ff4530b9da363b71e97ce60',
+        'com.android:zipflinger:4.1.1:zipflinger-4.1.1.jar:0a8c3e52ac13dd031236f9fb5ba4408b1d5dcd12325a05440b36da09d8881446',
        'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
        'com.google.code.gson:gson:2.8.5:gson-2.8.5.jar:233a0149fc365c9f6edbd683cfe266b19bdc773be98eabdaf6b3c924b48e7d81',
        'com.google.dagger:dagger-compiler:2.24:dagger-compiler-2.24.jar:3c5afb955fb188da485cb2c048eff37dce0e1530b9780a0f2f7187d16d1ccc1f',
@@ -35,27 +38,30 @@ dependencyVerification {
        'com.google.dagger:dagger-spi:2.24:dagger-spi-2.24.jar:c038445d14dbcb4054e61bf49e05009edf26fce4fdc7ec1a9db544784f68e718',
        'com.google.dagger:dagger:2.24:dagger-2.24.jar:550a6e46a6dfcdf1d764887b6090cea94f783327e50e5c73754f18facfc70b64',
        'com.google.errorprone:error_prone_annotations:2.2.0:error_prone_annotations-2.2.0.jar:6ebd22ca1b9d8ec06d41de8d64e0596981d9607b42035f9ed374f9de271a481a',
+        'com.google.errorprone:error_prone_annotations:2.3.2:error_prone_annotations-2.3.2.jar:357cd6cfb067c969226c442451502aee13800a24e950fdfde77bcdb4565a668d',
        'com.google.errorprone:javac-shaded:9-dev-r4023-3:javac-shaded-9-dev-r4023-3.jar:65bfccf60986c47fbc17c9ebab0be626afc41741e0a6ec7109e0768817a36f30',
        'com.google.googlejavaformat:google-java-format:1.5:google-java-format-1.5.jar:aa19ad7850fb85178aa22f2fddb163b84d6ce4d0035872f30d4408195ca1144e',
        'com.google.guava:failureaccess:1.0.1:failureaccess-1.0.1.jar:a171ee4c734dd2da837e4b16be9df4661afab72a41adaf31eb84dfdaf936ca26',
-        'com.google.guava:guava:27.0.1-jre:guava-27.0.1-jre.jar:e1c814fd04492a27c38e0317eabeaa1b3e950ec8010239e400fe90ad6c9107b4',
        'com.google.guava:guava:27.1-jre:guava-27.1-jre.jar:4a5aa70cc968a4d137e599ad37553e5cfeed2265e8c193476d7119036c536fe7',
+        'com.google.guava:guava:28.1-jre:guava-28.1-jre.jar:30beb8b8527bd07c6e747e77f1a92122c2f29d57ce347461a4a55eb26e382da4',
        'com.google.guava:listenablefuture:9999.0-empty-to-avoid-conflict-with-guava:listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar:b372a037d4230aa57fbeffdef30fd6123f9c0c2db85d0aced00c91b974f33f99',
        'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:2994a7eb78f2710bd3d3bfb639b2c94e219cedac0d4d084d516e78c16dddecf6',
+        'com.google.j2objc:j2objc-annotations:1.3:j2objc-annotations-1.3.jar:21af30c92267bd6122c0e0b4d20cccb6641a37eaf956c6540ec471d584e64a7b',
        'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
-        'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
+        'com.google.protobuf:protobuf-java:3.10.0:protobuf-java-3.10.0.jar:161d7d61a8cb3970891c299578702fd079646e032329d6c2cabf998d191437c9',
        'com.googlecode.json-simple:json-simple:1.1:json-simple-1.1.jar:2d9484f4c649f708f47f9a479465fc729770ee65617dca3011836602264f6439',
        'com.squareup:javapoet:1.11.1:javapoet-1.11.1.jar:9cbf2107be499ec6e95afd36b58e3ca122a24166cdd375732e51267d64058e90',
        'com.squareup:javawriter:2.5.0:javawriter-2.5.0.jar:fcfb09fb0ea0aa97d3cfe7ea792398081348e468f126b3603cb3803f240197f0',
        'com.sun.activation:javax.activation:1.2.0:javax.activation-1.2.0.jar:993302b16cd7056f21e779cc577d175a810bb4900ef73cd8fbf2b50f928ba9ce',
-        'com.sun.istack:istack-commons-runtime:2.21:istack-commons-runtime-2.21.jar:c33e67a0807095f02a0e2da139412dd7c4f9cc1a4c054b3e434f96831ba950f4',
-        'com.sun.xml.fastinfoset:FastInfoset:1.2.13:FastInfoset-1.2.13.jar:27a77db909f3c2833c0b1a37c55af1db06045118ad2eed96ce567b6632bce038',
+        'com.sun.istack:istack-commons-runtime:3.0.7:istack-commons-runtime-3.0.7.jar:6443e10ba2e259fb821d9b6becf10db5316285fc30c53cec9d7b19a3877e7fdf',
+        'com.sun.xml.fastinfoset:FastInfoset:1.2.15:FastInfoset-1.2.15.jar:785861db11ca1bd0d1956682b974ad73eb19cd3e01a4b3fa82d62eca97210aec',
        'commons-codec:commons-codec:1.10:commons-codec-1.10.jar:4241dfa94e711d435f29a4604a3e2de5c4aa3c165e23bd066be6fc1fc4309569',
        'commons-logging:commons-logging:1.2:commons-logging-1.2.jar:daddea1ea0be0f56978ab3006b8ac92834afeefbd9b7e4e6316fca57df0fa636',
        'it.unimi.dsi:fastutil:7.2.0:fastutil-7.2.0.jar:74fa208043740642f7e6eb09faba15965218ad2f50ce3020efb100136e4b591c',
+        'javax.activation:javax.activation-api:1.2.0:javax.activation-api-1.2.0.jar:43fdef0b5b6ceb31b0424b208b930c74ab58fac2ceeb7b3f6fd3aeb8b5ca4393',
        'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
        'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
-        'javax.xml.bind:jaxb-api:2.2.12-b140109.1041:jaxb-api-2.2.12-b140109.1041.jar:b5e60cd8b7b5ff01ce4a74c5dd008f4fbd14ced3495d0b47b85cfedc182211f2',
+        'javax.xml.bind:jaxb-api:2.3.1:jaxb-api-2.3.1.jar:88b955a0df57880a26a74708bc34f74dcaf8ebf4e78843a28b50eae945732b06',
        'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
        'net.ltgt.gradle.incap:incap:0.2:incap-0.2.jar:b625b9806b0f1e4bc7a2e3457119488de3cd57ea20feedd513db070a573a4ffd',
        'net.sf.jopt-simple:jopt-simple:4.9:jopt-simple-4.9.jar:26c5856e954b5f864db76f13b86919b59c6eecf9fd930b96baa8884626baf2f5',
@@ -69,35 +75,36 @@ dependencyVerification {
        'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
        'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
        'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-        'org.briarproject:obfs4proxy-android:0.0.11-2:obfs4proxy-android-0.0.11-2.zip:57e55cbe87aa2aac210fdbb6cd8cdeafe15f825406a08ebf77a8b787aa2c6a8a',
-        'org.briarproject:tor-android:0.3.5.10:tor-android-0.3.5.10.zip:edd83bf557fcff2105eaa0bdb3f607a6852ebe7360920929ae3039dd5f4774c5',
+        'org.briarproject:obfs4proxy-android:0.0.12-dev-40245c4a:obfs4proxy-android-0.0.12-dev-40245c4a.zip:8ab05a8f8391be2cb5ab2b665c281a06d9e3a756bd0f95a40a36ca927866ea82',
+        'org.briarproject:tor-android:0.3.5.13:tor-android-0.3.5.13.zip:e0978db136731dae07774b722970cdae1e462fb5adc82845dd80a7e2d87f356c',
        'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
        'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
+        'org.checkerframework:checker-qual:2.8.1:checker-qual-2.8.1.jar:9103499008bcecd4e948da29b17864abb64304e15706444ae209d17ebe0575df',
        'org.codehaus.groovy:groovy-all:2.4.15:groovy-all-2.4.15.jar:51d6c4e71782e85674239189499854359d380fb75e1a703756e3aaa5b98a5af0',
        'org.codehaus.mojo:animal-sniffer-annotations:1.17:animal-sniffer-annotations-1.17.jar:92654f493ecfec52082e76354f0ebf87648dc3d5cec2e3c3cdb947c016747a53',
-        'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',
-        'org.glassfish.jaxb:jaxb-runtime:2.2.11:jaxb-runtime-2.2.11.jar:a874f2351cfba8e2946be3002d10c18a6da8f21b52ba2acf52f2b85d5520ed70',
-        'org.glassfish.jaxb:txw2:2.2.11:txw2-2.2.11.jar:272a3ccad45a4511351920cd2a8633c53cab8d5220c7a92954da5526bb5eafea',
+        'org.codehaus.mojo:animal-sniffer-annotations:1.18:animal-sniffer-annotations-1.18.jar:47f05852b48ee9baefef80fa3d8cea60efa4753c0013121dd7fe5eef2e5c729d',
+        'org.glassfish.jaxb:jaxb-runtime:2.3.1:jaxb-runtime-2.3.1.jar:45fecfa5c8217ce1f3652ab95179790ec8cc0dec0384bca51cbeb94a293d9f2f',
+        'org.glassfish.jaxb:txw2:2.3.1:txw2-2.3.1.jar:34975dde1c6920f1a39791142235689bc3cd357e24d05edd8ff93b885bd68d60',
        'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
        'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
-        'org.jetbrains.kotlin:kotlin-reflect:1.3.50:kotlin-reflect-1.3.50.jar:64583199ea5a54aefd1bd1595288925f784226ee562d1dd279011c6075b3d7a4',
-        'org.jetbrains.kotlin:kotlin-stdlib-common:1.3.50:kotlin-stdlib-common-1.3.50.jar:8ce678e88e4ba018b66dacecf952471e4d7dfee156a8a819760a5a5ff29d323c',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.50:kotlin-stdlib-jdk7-1.3.50.jar:9a026639e76212f8d57b86d55b075394c2e009f1979110751d34c05c5f75d57b',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.50:kotlin-stdlib-jdk8-1.3.50.jar:1b351fb6e09c14b55525c74c1f4cf48942eae43c348b7bc764a5e6e423d4da0c',
-        'org.jetbrains.kotlin:kotlin-stdlib:1.3.50:kotlin-stdlib-1.3.50.jar:e6f05746ee0366d0b52825a090fac474dcf44082c9083bbb205bd16976488d6c',
+        'org.jetbrains.kotlin:kotlin-reflect:1.3.72:kotlin-reflect-1.3.72.jar:a188d9367de1c4ee9479db630985c0597b20709c83161b1430d24edb27e38c40',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.3.72:kotlin-stdlib-common-1.3.72.jar:5e7d1552863e480c1628b1cc39ce230ef829f5b7230106215a05acda5172203a',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.72:kotlin-stdlib-jdk7-1.3.72.jar:40566c0c08d414b9413ba556ff7f8a0b04b98b9f0f424d122dd2088510efccc4',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.72:kotlin-stdlib-jdk8-1.3.72.jar:133da70cfc07b56094282eac5c59bccd59f167ee2ead22e5282876d8bc10bf95',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.3.72:kotlin-stdlib-1.3.72.jar:3856a7349ebacd6d1be6802b2fed9c4dc2c5a564ea92b6b945ac988243d4b16b',
        'org.jetbrains.trove4j:trove4j:20160824:trove4j-20160824.jar:1917871c8deb468307a584680c87a44572f5a8b0b98c6d397fc0f5f86596dbe7',
        'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
        'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
        'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
        'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
        'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
-        'org.jvnet.staxex:stax-ex:1.7.7:stax-ex-1.7.7.jar:a31ff7d77163c0deb09e7fee59ad35ae44c2cee2cc8552a116ccd1583d813fb4',
+        'org.jvnet.staxex:stax-ex:1.8:stax-ex-1.8.jar:95b05d9590af4154c6513b9c5dc1fb2e55b539972ba0a9ef28e9a0c01d83ad77',
        'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
-        'org.ow2.asm:asm-analysis:6.0:asm-analysis-6.0.jar:2f1a6387219c3a6cc4856481f221b03bd9f2408a326d416af09af5d6f608c1f4',
-        'org.ow2.asm:asm-commons:6.0:asm-commons-6.0.jar:f1bce5c648a96a017bdcd01fe5d59af9845297fd7b79b81c015a6fbbd9719abf',
-        'org.ow2.asm:asm-tree:6.0:asm-tree-6.0.jar:887998fb69727c8759e4d253f856822801e33f9fd4caa566b3ac58ee92106215',
-        'org.ow2.asm:asm-util:6.0:asm-util-6.0.jar:356afebdb0f870175262e5188f8709a3b17aa2a5a6a4b0340b04d4b449bca5f6',
+        'org.ow2.asm:asm-analysis:7.0:asm-analysis-7.0.jar:e981f8f650c4d900bb033650b18e122fa6b161eadd5f88978d08751f72ee8474',
+        'org.ow2.asm:asm-commons:7.0:asm-commons-7.0.jar:fed348ef05958e3e846a3ac074a12af5f7936ef3d21ce44a62c4fa08a771927d',
+        'org.ow2.asm:asm-tree:7.0:asm-tree-7.0.jar:cfd7a0874f9de36a999c127feeadfbfe6e04d4a71ee954d7af3d853f0be48a6c',
+        'org.ow2.asm:asm-util:7.0:asm-util-7.0.jar:75fbbca440ef463f41c2b0ab1a80abe67e910ac486da60a7863cbcb5bae7e145',
        'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
-        'org.ow2.asm:asm:6.0:asm-6.0.jar:dd8971c74a4e697899a8e95caae4ea8760ea6c486dc6b97b1795e75760420461',
+        'org.ow2.asm:asm:7.0:asm-7.0.jar:b88ef66468b3c978ad0c97fd6e90979e56155b4ac69089ba7a44e9aa7ffe9acf',
    ]
 }
@@ -6,4 +6,10 @@ package org.briarproject.bramble.api;
 public interface FeatureFlags {

 	boolean shouldEnableImageAttachments();
+
+	boolean shouldEnableProfilePictures();
+
+	boolean shouldEnableDisappearingMessages();
+
+	boolean shouldEnableConnectViaBluetooth();
 }
@@ -0,0 +1,29 @@
+package org.briarproject.bramble.api.cleanup;
+
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.MessageId;
+
+import java.util.Collection;
+
+/**
+ * An interface for registering a hook with the {@link CleanupManager}
+ * that will be called when a message's cleanup deadline is reached.
+ */
+@NotNullByDefault
+public interface CleanupHook {
+
+	/**
+	 * Called when the cleanup deadlines of one or more messages are reached.
+	 * <p>
+	 * The callee is not required to delete the messages, but the hook won't be
+	 * called again for these messages unless another cleanup timer is set (see
+	 * {@link DatabaseComponent#setCleanupTimerDuration(Transaction, MessageId, long)}
+	 * and {@link DatabaseComponent#startCleanupTimer(Transaction, MessageId)}).
+	 */
+	void deleteMessages(Transaction txn, GroupId g,
+			Collection<MessageId> messageIds) throws DbException;
+}
@@ -0,0 +1,42 @@
+package org.briarproject.bramble.api.cleanup;
+
+import org.briarproject.bramble.api.cleanup.event.CleanupTimerStartedEvent;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.MessageId;
+
+/**
+ * The CleanupManager is responsible for tracking the cleanup deadlines of
+ * messages and passing them to their respective
+ * {@link CleanupHook CleanupHooks} when the deadlines are reached.
+ * <p>
+ * The CleanupManager responds to
+ * {@link CleanupTimerStartedEvent CleanupTimerStartedEvents} broadcast by the
+ * {@link DatabaseComponent}.
+ * <p>
+ * See {@link DatabaseComponent#setCleanupTimerDuration(Transaction, MessageId, long)},
+ * {@link DatabaseComponent#startCleanupTimer(Transaction, MessageId)},
+ * {@link DatabaseComponent#stopCleanupTimer(Transaction, MessageId)}.
+ */
+@NotNullByDefault
+public interface CleanupManager {
+
+	/**
+	 * When scheduling a cleanup task we overshoot the deadline by this many
+	 * milliseconds to reduce the number of tasks that need to be scheduled
+	 * when messages have cleanup deadlines that are close together.
+	 */
+	long BATCH_DELAY_MS = 1000;
+
+	/**
+	 * Registers a hook to be called when messages are due for cleanup.
+	 * This method should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerCleanupHook(ClientId c, int majorVersion,
+			CleanupHook hook);
+}
@@ -0,0 +1,32 @@
+package org.briarproject.bramble.api.cleanup.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a message's cleanup timer is started.
+ */
+@Immutable
+@NotNullByDefault
+public class CleanupTimerStartedEvent extends Event {
+
+	private final MessageId messageId;
+	private final long cleanupDeadline;
+
+	public CleanupTimerStartedEvent(MessageId messageId,
+			long cleanupDeadline) {
+		this.messageId = messageId;
+		this.cleanupDeadline = cleanupDeadline;
+	}
+
+	public MessageId getMessageId() {
+		return messageId;
+	}
+
+	public long getCleanupDeadline() {
+		return cleanupDeadline;
+	}
+}
@@ -1,6 +1,7 @@
 package org.briarproject.bramble.api.client;

 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
@@ -16,6 +17,7 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;

 import java.security.GeneralSecurityException;
+import java.util.Collection;
 import java.util.Map;

@NotNullByDefault
@@ -50,9 +52,11 @@ public interface ClientHelper {
 	BdfDictionary getGroupMetadataAsDictionary(Transaction txn, GroupId g)
 			throws DbException, FormatException;

+	Collection<MessageId> getMessageIds(Transaction txn, GroupId g,
+			BdfDictionary query) throws DbException, FormatException;
+
 	BdfDictionary getMessageMetadataAsDictionary(MessageId m)
-			throws DbException,
-			FormatException;
+			throws DbException, FormatException;

 	BdfDictionary getMessageMetadataAsDictionary(Transaction txn, MessageId m)
 			throws DbException, FormatException;
@@ -119,4 +123,17 @@ public interface ClientHelper {
 	Map<TransportId, TransportProperties> parseAndValidateTransportPropertiesMap(
 			BdfDictionary properties) throws FormatException;

+	/**
+	 * Retrieves the contact ID from the group metadata of the given contact
+	 * group.
+	 */
+	ContactId getContactId(Transaction txn, GroupId contactGroupId)
+			throws DbException, FormatException;
+
+	/**
+	 * Stores the given contact ID in the group metadata of the given contact
+	 * group.
+	 */
+	void setContactId(Transaction txn, GroupId contactGroupId, ContactId c)
+			throws DbException;
 }
@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.client;
+
+public interface ContactGroupConstants {
+
+	/**
+	 * Group metadata key for associating a contact ID with a contact group.
+	 */
+	String GROUP_KEY_CONTACT_ID = "contactId";
+}
@@ -11,7 +11,6 @@ import org.briarproject.bramble.api.db.PendingContactExistsException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

@@ -179,6 +178,11 @@ public interface ContactManager {
 	 */
 	Collection<Contact> getContacts() throws DbException;

+	/**
+	 * Returns all contacts.
+	 */
+	Collection<Contact> getContacts(Transaction txn) throws DbException;
+
 	/**
 	 * Removes a contact and all associated state.
 	 */
@@ -215,16 +219,6 @@ public interface ContactManager {
 	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;

-	/**
-	 * Returns the {@link AuthorInfo} for the given author.
-	 */
-	AuthorInfo getAuthorInfo(AuthorId a) throws DbException;
-
-	/**
-	 * Returns the {@link AuthorInfo} for the given author.
-	 */
-	AuthorInfo getAuthorInfo(Transaction txn, AuthorId a) throws DbException;
-
 	interface ContactHook {

 		/**
@@ -0,0 +1,35 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when the alias for a contact changed.
+ */
+@Immutable
+@NotNullByDefault
+public class ContactAliasChangedEvent extends Event {
+
+	private final ContactId contactId;
+	@Nullable
+	private final String alias;
+
+	public ContactAliasChangedEvent(ContactId contactId,
+			@Nullable String alias) {
+		this.contactId = contactId;
+		this.alias = alias;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	@Nullable
+	public String getAlias() {
+		return alias;
+	}
+}
@@ -5,9 +5,6 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 /**
 * Interface for strengthening a password-based key, for example by using a
 * key stored in a key management service or hardware security module.
- *
- * TODO: Remove after a reasonable migration period unless we can work around
- * Android keymaster bugs. Added 2020-02-24
 */
@NotNullByDefault
 public interface KeyStrengthener {
@@ -19,4 +19,10 @@ public interface StreamDecrypterFactory {
 	 */
 	StreamDecrypter createContactExchangeStreamDecrypter(InputStream in,
 			SecretKey headerKey);
+
+	/**
+	 * Creates a {@link StreamDecrypter} for decrypting a log stream.
+	 */
+	StreamDecrypter createLogStreamDecrypter(InputStream in,
+			SecretKey headerKey);
 }
@@ -17,6 +17,12 @@ public interface StreamEncrypterFactory {
 	 * Creates a {@link StreamEncrypter} for encrypting a contact exchange
 	 * stream.
 	 */
-	StreamEncrypter createContactExchangeStreamDecrypter(OutputStream out,
+	StreamEncrypter createContactExchangeStreamEncrypter(OutputStream out,
+			SecretKey headerKey);
+
+	/**
+	 * Creates a {@link StreamEncrypter} for encrypting a log stream.
+	 */
+	StreamEncrypter createLogStreamEncrypter(OutputStream out,
 			SecretKey headerKey);
 }
@@ -41,6 +41,18 @@ import javax.annotation.Nullable;
@NotNullByDefault
 public interface DatabaseComponent extends TransactionManager {

+	/**
+	 * Return value for {@link #getNextCleanupDeadline(Transaction)} if
+	 * no messages are scheduled to be deleted.
+	 */
+	long NO_CLEANUP_DEADLINE = -1;
+
+	/**
+	 * Return value for {@link #startCleanupTimer(Transaction, MessageId)}
+	 * if the cleanup timer was not started.
+	 */
+	long TIMER_NOT_STARTED = -1;
+
 	/**
 	 * Opens the database and returns true if the database already existed.
 	 *
@@ -288,6 +300,16 @@ public interface DatabaseComponent extends TransactionManager {
 	Collection<MessageId> getMessageIds(Transaction txn, GroupId g)
 			throws DbException;

+	/**
+	 * Returns the IDs of any delivered messages in the given group with
+	 * metadata that matches all entries in the given query. If the query is
+	 * empty, the IDs of all delivered messages are returned.
+	 * <p/>
+	 * Read-only.
+	 */
+	Collection<MessageId> getMessageIds(Transaction txn, GroupId g,
+			Metadata query) throws DbException;
+
 	/**
 	 * Returns the IDs of any messages that need to be validated.
 	 * <p/>
@@ -314,6 +336,15 @@ public interface DatabaseComponent extends TransactionManager {
 	Collection<MessageId> getMessagesToShare(Transaction txn)
 			throws DbException;

+	/**
+	 * Returns the IDs of any messages of any messages that are due for
+	 * deletion, along with their group IDs.
+	 * <p/>
+	 * Read-only.
+	 */
+	Map<GroupId, Collection<MessageId>> getMessagesToDelete(Transaction txn)
+			throws DbException;
+
 	/**
 	 * Returns the metadata for all delivered messages in the given group.
 	 * <p/>
@@ -395,6 +426,15 @@ public interface DatabaseComponent extends TransactionManager {
 	MessageStatus getMessageStatus(Transaction txn, ContactId c, MessageId m)
 			throws DbException;

+	/**
+	 * Returns the next time (in milliseconds since the Unix epoch) when a
+	 * message is due to be deleted, or {@link #NO_CLEANUP_DEADLINE}
+	 * if no messages are scheduled to be deleted.
+	 * <p/>
+	 * Read-only.
+	 */
+	long getNextCleanupDeadline(Transaction txn) throws DbException;
+
 	/*
 	 * Returns the next time (in milliseconds since the Unix epoch) when a
 	 * message is due to be sent to the given contact. The returned value may
@@ -535,6 +575,13 @@ public interface DatabaseComponent extends TransactionManager {
 	void removeTransportKeys(Transaction txn, TransportId t, KeySetId k)
 			throws DbException;

+	/**
+	 * Sets the cleanup timer duration for the given message. This does not
+	 * start the message's cleanup timer.
+	 */
+	void setCleanupTimerDuration(Transaction txn, MessageId m, long duration)
+			throws DbException;
+
 	/**
 	 * Marks the given contact as verified.
 	 */
@@ -557,6 +604,12 @@ public interface DatabaseComponent extends TransactionManager {
 	 */
 	void setMessagePermanent(Transaction txn, MessageId m) throws DbException;

+	/**
+	 * Marks the given message as not shared. This method is only meant for
+	 * testing.
+	 */
+	void setMessageNotShared(Transaction txn, MessageId m) throws DbException;
+
 	/**
 	 * Marks the given message as shared.
 	 */
@@ -599,6 +652,22 @@ public interface DatabaseComponent extends TransactionManager {
 	void setTransportKeysActive(Transaction txn, TransportId t, KeySetId k)
 			throws DbException;

+	/**
+	 * Starts the cleanup timer for the given message, if a timer duration
+	 * has been set and the timer has not already been started.
+	 *
+	 * @return The cleanup deadline, or {@link #TIMER_NOT_STARTED} if no
+	 * timer duration has been set for this message or its timer has already
+	 * been started.
+	 */
+	long startCleanupTimer(Transaction txn, MessageId m) throws DbException;
+
+	/**
+	 * Stops the cleanup timer for the given message, if the timer has been
+	 * started.
+	 */
+	void stopCleanupTimer(Transaction txn, MessageId m) throws DbException;
+
 	/**
 	 * Stores the given transport keys, deleting any keys they have replaced.
 	 */
@@ -57,6 +57,7 @@ public class Author implements Nameable {
 	/**
 	 * Returns the author's name.
 	 */
+	@Override
 	public String getName() {
 		return name;
 	}
@@ -3,7 +3,7 @@ package org.briarproject.bramble.api.keyagreement.event;
 import org.briarproject.bramble.api.event.Event;

 /**
- * An event that is broadcast when a BQP protocol completes.
+ * An event that is broadcast when a BQP protocol begins.
 */
 public class KeyAgreementStartedEvent extends Event {
 }
@@ -8,11 +8,12 @@ import javax.annotation.concurrent.Immutable;
@NotNullByDefault
 public class NetworkStatus {

-	private final boolean connected, wifi;
+	private final boolean connected, wifi, ipv6Only;

-	public NetworkStatus(boolean connected, boolean wifi) {
+	public NetworkStatus(boolean connected, boolean wifi, boolean ipv6Only) {
 		this.connected = connected;
 		this.wifi = wifi;
+		this.ipv6Only = ipv6Only;
 	}

 	public boolean isConnected() {
@@ -22,4 +23,8 @@ public class NetworkStatus {
 	public boolean isWifi() {
 		return wifi;
 	}
+
+	public boolean isIpv6Only() {
+		return ipv6Only;
+	}
 }
@@ -29,4 +29,12 @@ public class NullSafety {
 	public static void requireNull(@Nullable Object o) {
 		if (o != null) throw new AssertionError();
 	}
+
+	/**
+	 * Stand-in for {@code Objects.equals()}.
+	 */
+	public static boolean equals(@Nullable Object a, @Nullable Object b) {
+		return (a == b) || (a != null && a.equals(b));
+	}
+
 }
@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.plugin.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * An event that informs the Bluetooth plugin that we have enabled the
- * Bluetooth adapter.
- */
-@Immutable
-@NotNullByDefault
-public class BluetoothEnabledEvent extends Event {
-}
@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.plugin.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * An event that asks the Bluetooth plugin to disable the Bluetooth adapter if
- * we previously enabled it.
- */
-@Immutable
-@NotNullByDefault
-public class DisableBluetoothEvent extends Event {
-}
@@ -1,14 +0,0 @@
-package org.briarproject.bramble.api.plugin.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * An event that asks the Bluetooth plugin to enable the Bluetooth adapter.
- */
-@Immutable
-@NotNullByDefault
-public class EnableBluetoothEvent extends Event {
-}
@@ -13,4 +13,6 @@ public interface DevConfig {
 	String getDevOnionAddress();

 	File getReportDir();
+
+	File getLogcatFile();
 }
@@ -23,6 +23,8 @@ public interface DevReporter {

 	/**
 	 * Sends any reports previously stored on disk.
+	 *
+	 * @return The number of reports that were sent.
 	 */
-	void sendReports();
+	int sendReports();
 }
@@ -21,5 +21,6 @@ public interface ReportingConstants {
 	 * Hidden service address for reporting crashes and feedback to the
 	 * developers.
 	 */
-	String DEV_ONION_ADDRESS = "cwqmubyvnig3wag3.onion";
+	String DEV_ONION_ADDRESS =
+			"b2nkt5doeamvdmjzfz7g42hk5vdtlnktlgzhel2bgjcc4v4jhnx2qrqd.onion";
 }
@@ -16,8 +16,13 @@ public interface StreamReaderFactory {

 	/**
 	 * Creates an {@link InputStream InputStream} for reading from a contact
-	 * exchangestream.
+	 * exchange stream.
 	 */
 	InputStream createContactExchangeStreamReader(InputStream in,
 			SecretKey headerKey);
+
+	/**
+	 * Creates an {@link InputStream} for reading from a log stream.
+	 */
+	InputStream createLogStreamReader(InputStream in, SecretKey headerKey);
 }
@@ -7,17 +7,19 @@ import java.io.OutputStream;

@NotNullByDefault
 public interface StreamWriterFactory {
-
 	/**
-	 * Creates an {@link OutputStream OutputStream} for writing to a
-	 * transport stream
+	 * Creates a {@link StreamWriter} for writing to a transport stream.
 	 */
 	StreamWriter createStreamWriter(OutputStream out, StreamContext ctx);

 	/**
-	 * Creates an {@link OutputStream OutputStream} for writing to a contact
-	 * exchange stream.
+	 * Creates a {@link StreamWriter} for writing to a contact exchange stream.
 	 */
 	StreamWriter createContactExchangeStreamWriter(OutputStream out,
 			SecretKey headerKey);
+
+	/**
+	 * Creates a {@link StreamWriter} for writing to a log stream.
+	 */
+	StreamWriter createLogStreamWriter(OutputStream out, SecretKey headerKey);
 }
@@ -6,7 +6,9 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

 import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;

+@Immutable
@NotNullByDefault
 public class ValidationUtils {

@@ -64,4 +66,9 @@ public class ValidationUtils {
 		if (dictionary != null && dictionary.size() != size)
 			throw new FormatException();
 	}
+
+	public static void checkRange(@Nullable Long l, long min, long max)
+			throws FormatException {
+		if (l != null && (l < min || l > max)) throw new FormatException();
+	}
 }
@@ -1,42 +0,0 @@
-package org.briarproject.bramble.api.identity;
-
-import org.briarproject.bramble.test.BrambleTestCase;
-import org.junit.Test;
-
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.NONE;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-
-public class AuthorInfoTest extends BrambleTestCase {
-
-	@Test
-	public void testEquals() {
-		assertEquals(
-				new AuthorInfo(NONE),
-				new AuthorInfo(NONE, null)
-		);
-		assertEquals(
-				new AuthorInfo(NONE, "test"),
-				new AuthorInfo(NONE, "test")
-		);
-
-		assertNotEquals(
-				new AuthorInfo(NONE),
-				new AuthorInfo(VERIFIED)
-		);
-		assertNotEquals(
-				new AuthorInfo(NONE, "test"),
-				new AuthorInfo(NONE)
-		);
-		assertNotEquals(
-				new AuthorInfo(NONE),
-				new AuthorInfo(NONE, "test")
-		);
-		assertNotEquals(
-				new AuthorInfo(NONE, "a"),
-				new AuthorInfo(NONE, "b")
-		);
-	}
-
-}
@@ -0,0 +1,8 @@
+package org.briarproject.bramble.test;
+
+public interface TimeTravel {
+
+	void setCurrentTimeMillis(long now) throws InterruptedException;
+
+	void addCurrentTimeMillis(long add) throws InterruptedException;
+}
@@ -1,5 +1,6 @@
 package org.briarproject.bramble;

+import org.briarproject.bramble.cleanup.CleanupModule;
 import org.briarproject.bramble.contact.ContactModule;
 import org.briarproject.bramble.crypto.CryptoExecutorModule;
 import org.briarproject.bramble.db.DatabaseExecutorModule;
@@ -14,6 +15,8 @@ import org.briarproject.bramble.versioning.VersioningModule;

 public interface BrambleCoreEagerSingletons {

+	void inject(CleanupModule.EagerSingletons init);
+
 	void inject(ContactModule.EagerSingletons init);

 	void inject(CryptoExecutorModule.EagerSingletons init);
@@ -39,6 +42,7 @@ public interface BrambleCoreEagerSingletons {
 	class Helper {

 		public static void injectEagerSingletons(BrambleCoreEagerSingletons c) {
+			c.inject(new CleanupModule.EagerSingletons());
 			c.inject(new ContactModule.EagerSingletons());
 			c.inject(new CryptoExecutorModule.EagerSingletons());
 			c.inject(new DatabaseExecutorModule.EagerSingletons());
@@ -1,5 +1,6 @@
 package org.briarproject.bramble;

+import org.briarproject.bramble.cleanup.CleanupModule;
 import org.briarproject.bramble.client.ClientModule;
 import org.briarproject.bramble.connection.ConnectionModule;
 import org.briarproject.bramble.contact.ContactModule;
@@ -21,15 +22,14 @@ import org.briarproject.bramble.rendezvous.RendezvousModule;
 import org.briarproject.bramble.settings.SettingsModule;
 import org.briarproject.bramble.sync.SyncModule;
 import org.briarproject.bramble.sync.validation.ValidationModule;
-import org.briarproject.bramble.system.ClockModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;

 import dagger.Module;

@Module(includes = {
+		CleanupModule.class,
 		ClientModule.class,
-		ClockModule.class,
 		ConnectionModule.class,
 		ContactModule.class,
 		CryptoModule.class,
@@ -179,9 +179,8 @@ class AccountManagerImpl implements AccountManager {
 	@GuardedBy("stateChangeLock")
 	private boolean encryptAndStoreDatabaseKey(SecretKey key, String password) {
 		byte[] plaintext = key.getBytes();
-		// Don't use a key strengthener as the Android keymaster isn't reliable
-		byte[] ciphertext =
-				crypto.encryptWithPassword(plaintext, password, null);
+		byte[] ciphertext = crypto.encryptWithPassword(plaintext, password,
+				databaseConfig.getKeyStrengthener());
 		return storeEncryptedDatabaseKey(toHexString(ciphertext));
 	}

@@ -198,13 +197,13 @@ class AccountManagerImpl implements AccountManager {
 	@Override
 	public void signIn(String password) throws DecryptionException {
 		synchronized (stateChangeLock) {
-			databaseKey = loadAndDecryptDatabaseKey(password, false);
+			databaseKey = loadAndDecryptDatabaseKey(password);
 		}
 	}

 	@GuardedBy("stateChangeLock")
-	private SecretKey loadAndDecryptDatabaseKey(String password,
-			boolean changing) throws DecryptionException {
+	private SecretKey loadAndDecryptDatabaseKey(String password)
+			throws DecryptionException {
 		String hex = loadEncryptedDatabaseKey();
 		if (hex == null) {
 			LOG.warning("Failed to load encrypted database key");
@@ -215,11 +214,11 @@ class AccountManagerImpl implements AccountManager {
 		byte[] plaintext = crypto.decryptWithPassword(ciphertext, password,
 				keyStrengthener);
 		SecretKey key = new SecretKey(plaintext);
-		// If the DB key was encrypted with a hardware-backed key, re-encrypt
-		// it without the hardware-backed key so keymaster bugs don't delete
-		// the user's account
-		if (!changing && crypto.isEncryptedWithStrengthenedKey(ciphertext)) {
-			LOG.info("Re-encrypting database key without strengthened key");
+		// If the DB key was encrypted with a weak key and a key strengthener
+		// is now available, re-encrypt the DB key with a strengthened key
+		if (keyStrengthener != null &&
+				!crypto.isEncryptedWithStrengthenedKey(ciphertext)) {
+			LOG.info("Re-encrypting database key with strengthened key");
 			encryptAndStoreDatabaseKey(key, password);
 		}
 		return key;
@@ -229,7 +228,7 @@ class AccountManagerImpl implements AccountManager {
 	public void changePassword(String oldPassword, String newPassword)
 			throws DecryptionException {
 		synchronized (stateChangeLock) {
-			SecretKey key = loadAndDecryptDatabaseKey(oldPassword, true);
+			SecretKey key = loadAndDecryptDatabaseKey(oldPassword);
 			encryptAndStoreDatabaseKey(key, newPassword);
 		}
 	}
@@ -0,0 +1,159 @@
+package org.briarproject.bramble.cleanup;
+
+import org.briarproject.bramble.api.cleanup.CleanupHook;
+import org.briarproject.bramble.api.cleanup.CleanupManager;
+import org.briarproject.bramble.api.cleanup.event.CleanupTimerStartedEvent;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.lifecycle.Service;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.versioning.ClientMajorVersion;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
+
+import static java.lang.Math.max;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.db.DatabaseComponent.NO_CLEANUP_DEADLINE;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@ThreadSafe
+@NotNullByDefault
+class CleanupManagerImpl implements CleanupManager, Service, EventListener {
+
+	private static final Logger LOG =
+			getLogger(CleanupManagerImpl.class.getName());
+
+	private final Executor dbExecutor;
+	private final DatabaseComponent db;
+	private final TaskScheduler taskScheduler;
+	private final Clock clock;
+	private final Map<ClientMajorVersion, CleanupHook> hooks =
+			new ConcurrentHashMap<>();
+	private final Object lock = new Object();
+
+	@GuardedBy("lock")
+	private final Set<CleanupTask> pending = new HashSet<>();
+
+	@Inject
+	CleanupManagerImpl(@DatabaseExecutor Executor dbExecutor,
+			DatabaseComponent db, TaskScheduler taskScheduler, Clock clock) {
+		this.dbExecutor = dbExecutor;
+		this.db = db;
+		this.taskScheduler = taskScheduler;
+		this.clock = clock;
+	}
+
+	@Override
+	public void registerCleanupHook(ClientId c, int majorVersion,
+			CleanupHook hook) {
+		hooks.put(new ClientMajorVersion(c, majorVersion), hook);
+	}
+
+	@Override
+	public void startService() {
+		maybeScheduleTask(clock.currentTimeMillis());
+	}
+
+	@Override
+	public void stopService() {
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof CleanupTimerStartedEvent) {
+			CleanupTimerStartedEvent a = (CleanupTimerStartedEvent) e;
+			maybeScheduleTask(a.getCleanupDeadline());
+		}
+	}
+
+	private void maybeScheduleTask(long deadline) {
+		synchronized (lock) {
+			for (CleanupTask task : pending) {
+				if (task.deadline <= deadline) return;
+			}
+			CleanupTask task = new CleanupTask(deadline);
+			pending.add(task);
+			scheduleTask(task);
+		}
+	}
+
+	private void scheduleTask(CleanupTask task) {
+		long now = clock.currentTimeMillis();
+		long delay = max(0, task.deadline - now + BATCH_DELAY_MS);
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Scheduling cleanup task in " + delay + " ms");
+		}
+		taskScheduler.schedule(() -> deleteMessagesAndScheduleNextTask(task),
+				dbExecutor, delay, MILLISECONDS);
+	}
+
+	private void deleteMessagesAndScheduleNextTask(CleanupTask task) {
+		try {
+			synchronized (lock) {
+				pending.remove(task);
+			}
+			long deadline = db.transactionWithResult(false, txn -> {
+				deleteMessages(txn);
+				return db.getNextCleanupDeadline(txn);
+			});
+			if (deadline != NO_CLEANUP_DEADLINE) {
+				maybeScheduleTask(deadline);
+			}
+		} catch (DbException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
+	private void deleteMessages(Transaction txn) throws DbException {
+		Map<GroupId, Collection<MessageId>> ids = db.getMessagesToDelete(txn);
+		for (Entry<GroupId, Collection<MessageId>> e : ids.entrySet()) {
+			GroupId groupId = e.getKey();
+			Collection<MessageId> messageIds = e.getValue();
+			if (LOG.isLoggable(INFO)) {
+				LOG.info(messageIds.size() + " messages to delete");
+			}
+			for (MessageId m : messageIds) db.stopCleanupTimer(txn, m);
+			Group group = db.getGroup(txn, groupId);
+			ClientMajorVersion cv = new ClientMajorVersion(group.getClientId(),
+					group.getMajorVersion());
+			CleanupHook hook = hooks.get(cv);
+			if (hook == null) {
+				throw new IllegalStateException("No cleanup hook for " + cv);
+			}
+			hook.deleteMessages(txn, groupId, messageIds);
+		}
+	}
+
+	private static class CleanupTask {
+
+		private final long deadline;
+
+		private CleanupTask(long deadline) {
+			this.deadline = deadline;
+		}
+	}
+}
@@ -0,0 +1,29 @@
+package org.briarproject.bramble.cleanup;
+
+import org.briarproject.bramble.api.cleanup.CleanupManager;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class CleanupModule {
+
+	public static class EagerSingletons {
+		@Inject
+		CleanupManager cleanupManager;
+	}
+
+	@Provides
+	@Singleton
+	CleanupManager provideCleanupManager(LifecycleManager lifecycleManager,
+			EventBus eventBus, CleanupManagerImpl cleanupManager) {
+		lifecycleManager.registerService(cleanupManager);
+		eventBus.addListener(cleanupManager);
+		return cleanupManager;
+	}
+}
@@ -2,11 +2,13 @@ package org.briarproject.bramble.client;

 import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfEntry;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.BdfReader;
 import org.briarproject.bramble.api.data.BdfReaderFactory;
@@ -32,6 +34,7 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.security.GeneralSecurityException;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -39,6 +42,7 @@ import java.util.Map.Entry;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;

+import static org.briarproject.bramble.api.client.ContactGroupConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
@@ -151,6 +155,12 @@ class ClientHelperImpl implements ClientHelper {
 		return metadataParser.parse(metadata);
 	}

+	@Override
+	public Collection<MessageId> getMessageIds(Transaction txn, GroupId g,
+			BdfDictionary query) throws DbException, FormatException {
+		return db.getMessageIds(txn, g, metadataEncoder.encode(query));
+	}
+
 	@Override
 	public BdfDictionary getMessageMetadataAsDictionary(MessageId m)
 			throws DbException, FormatException {
@@ -389,4 +399,27 @@ class ClientHelperImpl implements ClientHelper {
 		return tpMap;
 	}

+	@Override
+	public ContactId getContactId(Transaction txn, GroupId contactGroupId)
+			throws DbException {
+		try {
+			BdfDictionary meta =
+					getGroupMetadataAsDictionary(txn, contactGroupId);
+			return new ContactId(meta.getLong(GROUP_KEY_CONTACT_ID).intValue());
+		} catch (FormatException e) {
+			throw new DbException(e); // Invalid group metadata
+		}
+	}
+
+	@Override
+	public void setContactId(Transaction txn, GroupId contactGroupId,
+			ContactId c) throws DbException {
+		BdfDictionary meta = BdfDictionary.of(
+				new BdfEntry(GROUP_KEY_CONTACT_ID, c.getInt()));
+		try {
+			mergeGroupMetadata(txn, contactGroupId, meta);
+		} catch (FormatException e) {
+			throw new AssertionError(e);
+		}
+	}
 }
@@ -20,9 +20,7 @@ import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.transport.KeyManager;

@@ -40,10 +38,6 @@ import javax.inject.Inject;

 import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
 import static org.briarproject.bramble.util.StringUtils.toUtf8;

@ThreadSafe
@@ -213,6 +207,11 @@ class ContactManagerImpl implements ContactManager, EventListener {
 		return db.transactionWithResult(true, db::getContacts);
 	}

+	@Override
+	public Collection<Contact> getContacts(Transaction txn) throws DbException {
+		return db.getContacts(txn);
+	}
+
 	@Override
 	public void removeContact(ContactId c) throws DbException {
 		db.transaction(false, txn -> removeContact(txn, c));
@@ -256,25 +255,6 @@ class ContactManagerImpl implements ContactManager, EventListener {
 		db.removeContact(txn, c);
 	}

-	@Override
-	public AuthorInfo getAuthorInfo(AuthorId a) throws DbException {
-		return db.transactionWithResult(true, txn -> getAuthorInfo(txn, a));
-	}
-
-	@Override
-	public AuthorInfo getAuthorInfo(Transaction txn, AuthorId authorId)
-			throws DbException {
-		LocalAuthor localAuthor = identityManager.getLocalAuthor(txn);
-		if (localAuthor.getId().equals(authorId))
-			return new AuthorInfo(OURSELVES);
-		Collection<Contact> contacts = db.getContactsByAuthorId(txn, authorId);
-		if (contacts.isEmpty()) return new AuthorInfo(UNKNOWN);
-		if (contacts.size() > 1) throw new AssertionError();
-		Contact c = contacts.iterator().next();
-		if (c.isVerified()) return new AuthorInfo(VERIFIED, c.getAlias());
-		else return new AuthorInfo(UNVERIFIED, c.getAlias());
-	}
-
 	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof PendingContactStateChangedEvent) {
@@ -11,6 +11,7 @@ import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.Base32;

 import java.security.GeneralSecurityException;
+import java.util.Locale;
 import java.util.regex.Matcher;

 import javax.inject.Inject;
@@ -52,7 +53,7 @@ class PendingContactFactoryImpl implements PendingContactFactory {
 		byte[] raw = new byte[RAW_LINK_BYTES];
 		raw[0] = FORMAT_VERSION;
 		arraycopy(encoded, 0, raw, 1, encoded.length);
-		return "briar://" + Base32.encode(raw).toLowerCase();
+		return "briar://" + Base32.encode(raw).toLowerCase(Locale.US);
 	}

 	private PublicKey parseHandshakeLink(String link) throws FormatException {
@@ -9,14 +9,16 @@ import java.util.logging.Logger;

 import javax.inject.Inject;

+import static java.lang.Math.min;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;

 class ScryptKdf implements PasswordBasedKdf {

 	private static final Logger LOG =
-			Logger.getLogger(ScryptKdf.class.getName());
+			getLogger(ScryptKdf.class.getName());

 	private static final int MIN_COST = 256; // Min parameter N
 	private static final int MAX_COST = 1024 * 1024; // Max parameter N
@@ -33,10 +35,20 @@ class ScryptKdf implements PasswordBasedKdf {

 	@Override
 	public int chooseCostParameter() {
+		// Scrypt uses at least 128 * N * r bytes of memory. Don't use more
+		// than half of the JVM's max heap size or we may run out of memory.
+		// https://blog.filippo.io/the-scrypt-parameters/
+		long maxMemory = Runtime.getRuntime().maxMemory();
+		long maxCost = min(MAX_COST, maxMemory / BLOCK_SIZE / 256);
+		if (LOG.isLoggable(INFO) && maxCost < MAX_COST) {
+			LOG.info("Max cost capped at " + maxCost
+					+ " due to max heap size " + maxMemory);
+		}
 		// Increase the cost from min to max while measuring performance
 		int cost = MIN_COST;
-		while (cost * 2 <= MAX_COST && measureDuration(cost) * 2 <= TARGET_MS)
+		while (cost * 2 <= maxCost && measureDuration(cost) * 2 <= TARGET_MS) {
 			cost *= 2;
+		}
 		if (LOG.isLoggable(INFO))
 			LOG.info("KDF cost parameter " + cost);
 		return cost;
@@ -36,4 +36,10 @@ class StreamDecrypterFactoryImpl implements StreamDecrypterFactory {
 			SecretKey headerKey) {
 		return new StreamDecrypterImpl(in, cipherProvider.get(), 0, headerKey);
 	}
+
+	@Override
+	public StreamDecrypter createLogStreamDecrypter(InputStream in,
+			SecretKey headerKey) {
+		return createContactExchangeStreamDecrypter(in, headerKey);
+	}
 }
@@ -51,7 +51,7 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 	}

 	@Override
-	public StreamEncrypter createContactExchangeStreamDecrypter(
+	public StreamEncrypter createContactExchangeStreamEncrypter(
 			OutputStream out, SecretKey headerKey) {
 		AuthenticatedCipher cipher = cipherProvider.get();
 		byte[] streamHeaderNonce = new byte[STREAM_HEADER_NONCE_LENGTH];
@@ -60,4 +60,10 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 		return new StreamEncrypterImpl(out, cipher, 0, null, streamHeaderNonce,
 				headerKey, frameKey);
 	}
+
+	@Override
+	public StreamEncrypter createLogStreamEncrypter(OutputStream out,
+			SecretKey headerKey) {
+		return createContactExchangeStreamEncrypter(out, headerKey);
+	}
 }
@@ -68,6 +68,13 @@ interface Database<T> {
 	 */
 	void close() throws DbException;

+	/**
+	 * Returns true if the dirty flag was set while opening the database,
+	 * indicating that the database has not been shut down properly the last
+	 * time it was closed and some data could be lost.
+	 */
+	boolean wasDirtyOnInitialisation();
+
 	/**
 	 * Starts a new transaction and returns an object representing it.
 	 */
@@ -497,6 +504,25 @@ interface Database<T> {
 	 */
 	Collection<MessageId> getMessagesToShare(T txn) throws DbException;

+	/**
+	 * Returns the IDs of any messages of any messages that are due for
+	 * deletion, along with their group IDs.
+	 * <p/>
+	 * Read-only.
+	 */
+	Map<GroupId, Collection<MessageId>> getMessagesToDelete(T txn)
+			throws DbException;
+
+	/**
+	 * Returns the next time (in milliseconds since the Unix epoch) when a
+	 * message is due to be deleted, or
+	 * {@link DatabaseComponent#NO_CLEANUP_DEADLINE} if no messages are
+	 * scheduled to be deleted.
+	 * <p/>
+	 * Read-only.
+	 */
+	long getNextCleanupDeadline(T txn) throws DbException;
+
 	/**
 	 * Returns the next time (in milliseconds since the Unix epoch) when a
 	 * message is due to be sent to the given contact. The returned value may
@@ -606,8 +632,10 @@ interface Database<T> {

 	/**
 	 * Marks a message as having been seen by the given contact.
+	 *
+	 * @return True if the message was not already marked as seen.
 	 */
-	void raiseSeenFlag(T txn, ContactId c, MessageId m) throws DbException;
+	boolean raiseSeenFlag(T txn, ContactId c, MessageId m) throws DbException;

 	/**
 	 * Removes a contact from the database.
@@ -671,6 +699,13 @@ interface Database<T> {
 	 */
 	void resetExpiryTime(T txn, ContactId c, MessageId m) throws DbException;

+	/**
+	 * Sets the cleanup timer duration for the given message. This does not
+	 * start the message's cleanup timer.
+	 */
+	void setCleanupTimerDuration(T txn, MessageId m, long duration)
+			throws DbException;
+
 	/**
 	 * Marks the given contact as verified.
 	 */
@@ -701,9 +736,10 @@ interface Database<T> {
 	void setMessagePermanent(T txn, MessageId m) throws DbException;

 	/**
-	 * Marks the given message as shared.
+	 * Marks the given message as shared or not.
 	 */
-	void setMessageShared(T txn, MessageId m) throws DbException;
+	void setMessageShared(T txn, MessageId m, boolean shared)
+			throws DbException;

 	/**
 	 * Sets the validation and delivery state of the given message.
@@ -730,6 +766,22 @@ interface Database<T> {
 	void setTransportKeysActive(T txn, TransportId t, KeySetId k)
 			throws DbException;

+	/**
+	 * Starts the cleanup timer for the given message, if a timer duration
+	 * has been set and the timer has not already been started.
+	 *
+	 * @return The cleanup deadline, or
+	 * {@link DatabaseComponent#TIMER_NOT_STARTED} if no timer duration has
+	 * been set for this message or its timer has already been started.
+	 */
+	long startCleanupTimer(T txn, MessageId m) throws DbException;
+
+	/**
+	 * Stops the cleanup timer for the given message, if the timer has been
+	 * started.
+	 */
+	void stopCleanupTimer(T txn, MessageId m) throws DbException;
+
 	/**
 	 * Updates the transmission count, expiry time and estimated time of arrival
 	 * of the given message with respect to the given contact, using the latency
@@ -1,10 +1,12 @@
 package org.briarproject.bramble.db;

+import org.briarproject.bramble.api.cleanup.event.CleanupTimerStartedEvent;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.PendingContact;
 import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
+import org.briarproject.bramble.api.contact.event.ContactAliasChangedEvent;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.contact.event.ContactVerifiedEvent;
 import org.briarproject.bramble.api.contact.event.PendingContactAddedEvent;
@@ -576,6 +578,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getMessageIds(txn, g);
 	}

+	@Override
+	public Collection<MessageId> getMessageIds(Transaction transaction,
+			GroupId g, Metadata query) throws DbException {
+		T txn = unbox(transaction);
+		if (!db.containsGroup(txn, g))
+			throw new NoSuchGroupException();
+		return db.getMessageIds(txn, g, query);
+	}
+
 	@Override
 	public Collection<MessageId> getMessagesToValidate(Transaction transaction)
 			throws DbException {
@@ -597,6 +608,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getMessagesToShare(txn);
 	}

+	@Override
+	public Map<GroupId, Collection<MessageId>> getMessagesToDelete(
+			Transaction transaction) throws DbException {
+		T txn = unbox(transaction);
+		return db.getMessagesToDelete(txn);
+	}
+
 	@Override
 	public Map<MessageId, Metadata> getMessageMetadata(Transaction transaction,
 			GroupId g) throws DbException {
@@ -692,6 +710,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getMessageDependents(txn, m);
 	}

+	@Override
+	public long getNextCleanupDeadline(Transaction transaction)
+			throws DbException {
+		T txn = unbox(transaction);
+		return db.getNextCleanupDeadline(txn);
+	}
+
 	@Override
 	public long getNextSendTime(Transaction transaction, ContactId c)
 			throws DbException {
@@ -795,8 +820,17 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		Collection<MessageId> acked = new ArrayList<>();
 		for (MessageId m : a.getMessageIds()) {
 			if (db.containsVisibleMessage(txn, c, m)) {
-				db.raiseSeenFlag(txn, c, m);
-				acked.add(m);
+				if (db.raiseSeenFlag(txn, c, m)) {
+					// This is the first time the message has been acked by
+					// this contact. Start the cleanup timer (a no-op unless
+					// a cleanup deadline has been set for this message)
+					long deadline = db.startCleanupTimer(txn, m);
+					if (deadline != TIMER_NOT_STARTED) {
+						transaction.attach(new CleanupTimerStartedEvent(m,
+								deadline));
+					}
+					acked.add(m);
+				}
 			}
 		}
 		if (acked.size() > 0) {
@@ -952,6 +986,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.removeTransportKeys(txn, t, k);
 	}

+	@Override
+	public void setCleanupTimerDuration(Transaction transaction, MessageId m,
+			long duration) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		db.setCleanupTimerDuration(txn, m, duration);
+	}
+
 	@Override
 	public void setContactVerified(Transaction transaction, ContactId c)
 			throws DbException {
@@ -970,6 +1014,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
+		transaction.attach(new ContactAliasChangedEvent(c, alias));
 		db.setContactAlias(txn, c, alias);
 	}

@@ -1001,6 +1046,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.setMessagePermanent(txn, m);
 	}

+	@Override
+	public void setMessageNotShared(Transaction transaction, MessageId m)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		db.setMessageShared(txn, m, false);
+	}
+
 	@Override
 	public void setMessageShared(Transaction transaction, MessageId m)
 			throws DbException {
@@ -1010,7 +1065,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchMessageException();
 		if (db.getMessageState(txn, m) != DELIVERED)
 			throw new IllegalArgumentException("Shared undelivered message");
-		db.setMessageShared(txn, m);
+		db.setMessageShared(txn, m, true);
 		transaction.attach(new MessageSharedEvent(m));
 	}

@@ -1082,6 +1137,30 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.setTransportKeysActive(txn, t, k);
 	}

+	@Override
+	public long startCleanupTimer(Transaction transaction, MessageId m)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		long deadline = db.startCleanupTimer(txn, m);
+		if (deadline != TIMER_NOT_STARTED) {
+			transaction.attach(new CleanupTimerStartedEvent(m, deadline));
+		}
+		return deadline;
+	}
+
+	@Override
+	public void stopCleanupTimer(Transaction transaction, MessageId m)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		db.stopCleanupTimer(txn, m);
+	}
+
 	@Override
 	public void updateTransportKeys(Transaction transaction,
 			Collection<TransportKeySet> keys) throws DbException {
@@ -37,4 +37,10 @@ interface DatabaseConstants {
 	 * has passed since the last compaction.
 	 */
 	long MAX_COMPACTION_INTERVAL_MS = DAYS.toMillis(30);
+
+	/**
+	 * The {@link Settings} key under which the flag is stored indicating
+	 * whether the database is marked as dirty.
+	 */
+	String DIRTY_KEY = "dirty";
 }
@@ -84,9 +84,14 @@ class H2Database extends JdbcDatabase {
 	@Override
 	public void close() throws DbException {
 		// H2 will close the database when the last connection closes
+		Connection c = null;
 		try {
+			c = createConnection();
 			super.closeAllConnections();
+			setDirty(c, false);
+			c.close();
 		} catch (SQLException e) {
+			tryToClose(c, LOG, WARNING);
 			throw new DbException(e);
 		}
 	}
@@ -81,6 +81,7 @@ class HyperSqlDatabase extends JdbcDatabase {
 		try {
 			super.closeAllConnections();
 			c = createConnection();
+			setDirty(c, false);
 			s = c.createStatement();
 			s.executeQuery("SHUTDOWN");
 			s.close();
@@ -72,6 +72,8 @@ import static java.util.Arrays.asList;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.db.DatabaseComponent.NO_CLEANUP_DEADLINE;
+import static org.briarproject.bramble.api.db.DatabaseComponent.TIMER_NOT_STARTED;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
@@ -81,6 +83,7 @@ import static org.briarproject.bramble.api.sync.validation.MessageState.DELIVERE
 import static org.briarproject.bramble.api.sync.validation.MessageState.PENDING;
 import static org.briarproject.bramble.api.sync.validation.MessageState.UNKNOWN;
 import static org.briarproject.bramble.db.DatabaseConstants.DB_SETTINGS_NAMESPACE;
+import static org.briarproject.bramble.db.DatabaseConstants.DIRTY_KEY;
 import static org.briarproject.bramble.db.DatabaseConstants.LAST_COMPACTED_KEY;
 import static org.briarproject.bramble.db.DatabaseConstants.MAX_COMPACTION_INTERVAL_MS;
 import static org.briarproject.bramble.db.DatabaseConstants.SCHEMA_VERSION_KEY;
@@ -98,7 +101,7 @@ import static org.briarproject.bramble.util.LogUtils.now;
 abstract class JdbcDatabase implements Database<Connection> {

 	// Package access for testing
-	static final int CODE_SCHEMA_VERSION = 47;
+	static final int CODE_SCHEMA_VERSION = 48;

 	// Time period offsets for incoming transport keys
 	private static final int OFFSET_PREV = -1;
@@ -180,6 +183,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " state INT NOT NULL,"
 					+ " shared BOOLEAN NOT NULL,"
 					+ " temporary BOOLEAN NOT NULL,"
+					// Null if no timer duration has been set
+					+ " cleanupTimerDuration BIGINT,"
+					// Null if no timer duration has been set or the timer
+					// hasn't started
+					+ " cleanupDeadline BIGINT,"
 					+ " length INT NOT NULL,"
 					+ " raw BLOB," // Null if message has been deleted
 					+ " PRIMARY KEY (messageId),"
@@ -336,6 +344,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 			"CREATE INDEX IF NOT EXISTS statusesByContactIdTimestamp"
 					+ " ON statuses (contactId, timestamp)";

+	private static final String INDEX_MESSAGES_BY_CLEANUP_DEADLINE =
+			"CREATE INDEX IF NOT EXISTS messagesByCleanupDeadline"
+					+ " ON messages (cleanupDeadline)";
+
 	private static final Logger LOG =
 			getLogger(JdbcDatabase.class.getName());

@@ -354,9 +366,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 	@GuardedBy("connectionsLock")
 	private boolean closed = false;

+	private volatile boolean wasDirtyOnInitialisation = false;
+
 	protected abstract Connection createConnection()
 			throws DbException, SQLException;

+	// Used exclusively during open to compact the database after schema
+	// migrations or after DatabaseConstants#MAX_COMPACTION_INTERVAL_MS has
+	// elapsed
 	protected abstract void compactAndClose() throws DbException;

 	JdbcDatabase(DatabaseTypes databaseTypes, MessageFactory messageFactory,
@@ -381,13 +398,19 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			if (reopen) {
 				Settings s = getSettings(txn, DB_SETTINGS_NAMESPACE);
+				wasDirtyOnInitialisation = isDirty(s);
 				compact = migrateSchema(txn, s, listener) || isCompactionDue(s);
 			} else {
+				wasDirtyOnInitialisation = false;
 				createTables(txn);
 				initialiseSettings(txn);
 				compact = false;
 			}
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("db dirty? " + wasDirtyOnInitialisation);
+			}
 			createIndexes(txn);
+			setDirty(txn, true);
 			commitTransaction(txn);
 		} catch (DbException e) {
 			abortTransaction(txn);
@@ -414,6 +437,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	@Override
+	public boolean wasDirtyOnInitialisation() {
+		return wasDirtyOnInitialisation;
+	}
+
 	/**
 	 * Compares the schema version stored in the database with the schema
 	 * version used by the current code and applies any suitable migrations to
@@ -463,7 +491,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 				new Migration43_44(dbTypes),
 				new Migration44_45(),
 				new Migration45_46(),
-				new Migration46_47(dbTypes)
+				new Migration46_47(dbTypes),
+				new Migration47_48()
 		);
 	}

@@ -488,6 +517,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 		mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
 	}

+	private boolean isDirty(Settings s) {
+		return s.getBoolean(DIRTY_KEY, false);
+	}
+
+	protected void setDirty(Connection txn, boolean dirty) throws DbException {
+		Settings s = new Settings();
+		s.putBoolean(DIRTY_KEY, dirty);
+		mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
+	}
+
 	private void initialiseSettings(Connection txn) throws DbException {
 		Settings s = new Settings();
 		s.putInt(SCHEMA_VERSION_KEY, CODE_SCHEMA_VERSION);
@@ -531,6 +570,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			s.executeUpdate(INDEX_MESSAGE_DEPENDENCIES_BY_DEPENDENCY_ID);
 			s.executeUpdate(INDEX_STATUSES_BY_CONTACT_ID_GROUP_ID);
 			s.executeUpdate(INDEX_STATUSES_BY_CONTACT_ID_TIMESTAMP);
+			s.executeUpdate(INDEX_MESSAGES_BY_CLEANUP_DEADLINE);
 			s.close();
 		} catch (SQLException e) {
 			tryToClose(s, LOG, WARNING);
@@ -1290,7 +1330,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 	public void deleteMessage(Connection txn, MessageId m) throws DbException {
 		PreparedStatement ps = null;
 		try {
-			String sql = "UPDATE messages SET raw = NULL WHERE messageId = ?";
+			String sql = "UPDATE messages"
+					+ " SET raw = NULL, cleanupDeadline = NULL"
+					+ " WHERE messageId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			int affected = ps.executeUpdate();
@@ -1769,7 +1811,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 				// Return early if there are no matches
 				if (intersection.isEmpty()) return Collections.emptySet();
 			}
-			if (intersection == null) throw new AssertionError();
 			return intersection;
 		} catch (SQLException e) {
 			tryToClose(rs, LOG, WARNING);
@@ -2226,6 +2267,39 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	@Override
+	public Map<GroupId, Collection<MessageId>> getMessagesToDelete(
+			Connection txn) throws DbException {
+		long now = clock.currentTimeMillis();
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT messageId, groupId FROM messages"
+					+ " WHERE cleanupDeadline <= ?";
+			ps = txn.prepareStatement(sql);
+			ps.setLong(1, now);
+			rs = ps.executeQuery();
+			Map<GroupId, Collection<MessageId>> ids = new HashMap<>();
+			while (rs.next()) {
+				MessageId m = new MessageId(rs.getBytes(1));
+				GroupId g = new GroupId(rs.getBytes(2));
+				Collection<MessageId> messageIds = ids.get(g);
+				if (messageIds == null) {
+					messageIds = new ArrayList<>();
+					ids.put(g, messageIds);
+				}
+				messageIds.add(m);
+			}
+			rs.close();
+			ps.close();
+			return ids;
+		} catch (SQLException e) {
+			tryToClose(rs, LOG, WARNING);
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public long getNextSendTime(Connection txn, ContactId c)
 			throws DbException {
@@ -2256,6 +2330,31 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	@Override
+	public long getNextCleanupDeadline(Connection txn) throws DbException {
+		Statement s = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT cleanupDeadline FROM messages"
+					+ " WHERE cleanupDeadline IS NOT NULL"
+					+ " ORDER BY cleanupDeadline LIMIT 1";
+			s = txn.createStatement();
+			rs = s.executeQuery(sql);
+			long nextDeadline = NO_CLEANUP_DEADLINE;
+			if (rs.next()) {
+				nextDeadline = rs.getLong(1);
+				if (rs.next()) throw new AssertionError();
+			}
+			rs.close();
+			s.close();
+			return nextDeadline;
+		} catch (SQLException e) {
+			tryToClose(rs, LOG, WARNING);
+			tryToClose(s, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public PendingContact getPendingContact(Connection txn, PendingContactId p)
 			throws DbException {
@@ -2776,7 +2875,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public void raiseSeenFlag(Connection txn, ContactId c, MessageId m)
+	public boolean raiseSeenFlag(Connection txn, ContactId c, MessageId m)
 			throws DbException {
 		PreparedStatement ps = null;
 		try {
@@ -2788,6 +2887,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int affected = ps.executeUpdate();
 			if (affected < 0 || affected > 1) throw new DbStateException();
 			ps.close();
+			return affected == 1;
 		} catch (SQLException e) {
 			tryToClose(ps, LOG, WARNING);
 			throw new DbException(e);
@@ -3021,6 +3121,25 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	@Override
+	public void setCleanupTimerDuration(Connection txn, MessageId m,
+			long duration) throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE messages SET cleanupTimerDuration = ?"
+					+ " WHERE messageId = ? AND cleanupTimerDuration IS NULL";
+			ps = txn.prepareStatement(sql);
+			ps.setLong(1, duration);
+			ps.setBytes(2, m.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected < 0 || affected > 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void setContactVerified(Connection txn, ContactId c)
 			throws DbException {
@@ -3128,22 +3247,24 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public void setMessageShared(Connection txn, MessageId m)
+	public void setMessageShared(Connection txn, MessageId m, boolean shared)
 			throws DbException {
 		PreparedStatement ps = null;
 		try {
-			String sql = "UPDATE messages SET shared = TRUE"
+			String sql = "UPDATE messages SET shared = ?"
 					+ " WHERE messageId = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, m.getBytes());
+			ps.setBoolean(1, shared);
+			ps.setBytes(2, m.getBytes());
 			int affected = ps.executeUpdate();
 			if (affected < 0 || affected > 1) throw new DbStateException();
 			ps.close();
 			// Update denormalised column in statuses
-			sql = "UPDATE statuses SET messageShared = TRUE"
+			sql = "UPDATE statuses SET messageShared = ?"
 					+ " WHERE messageId = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, m.getBytes());
+			ps.setBoolean(1, shared);
+			ps.setBytes(2, m.getBytes());
 			affected = ps.executeUpdate();
 			if (affected < 0) throw new DbStateException();
 			ps.close();
@@ -3272,6 +3393,60 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	@Override
+	public long startCleanupTimer(Connection txn, MessageId m)
+			throws DbException {
+		long now = clock.currentTimeMillis();
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "UPDATE messages"
+					+ " SET cleanupDeadline = ? + cleanupTimerDuration"
+					+ " WHERE messageId = ?"
+					+ " AND cleanupTimerDuration IS NOT NULL"
+					+ " AND cleanupDeadline IS NULL";
+			ps = txn.prepareStatement(sql);
+			ps.setLong(1, now);
+			ps.setBytes(2, m.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected < 0 || affected > 1) throw new DbStateException();
+			ps.close();
+			if (affected == 0) return TIMER_NOT_STARTED;
+			sql = "SELECT cleanupDeadline FROM messages WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			long deadline = rs.getLong(1);
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return deadline;
+		} catch (SQLException e) {
+			tryToClose(rs, LOG, WARNING);
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public void stopCleanupTimer(Connection txn, MessageId m)
+			throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE messages SET cleanupDeadline = NULL"
+					+ " WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected < 0 || affected > 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void updateExpiryTimeAndEta(Connection txn, ContactId c, MessageId m,
 			int maxLatency) throws DbException {
@@ -0,0 +1,47 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+
+class Migration47_48 implements Migration<Connection> {
+
+	private static final Logger LOG = getLogger(Migration47_48.class.getName());
+
+	@Override
+	public int getStartVersion() {
+		return 47;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 48;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			// Null if no timer duration has been set
+			s.execute("ALTER TABLE messages"
+					+ " ADD COLUMN cleanupTimerDuration BIGINT");
+			// Null if no timer duration has been set or the timer
+			// hasn't started
+			s.execute("ALTER TABLE messages"
+					+ " ADD COLUMN cleanupDeadline BIGINT");
+			s.execute("CREATE INDEX IF NOT EXISTS messagesByCleanupDeadline"
+					+ " ON messages (cleanupDeadline)");
+		} catch (SQLException e) {
+			tryToClose(s, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+}
@@ -1,5 +1,6 @@
 package org.briarproject.bramble.keyagreement;

+import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.data.BdfList;
@@ -8,6 +9,8 @@ import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.keyagreement.Payload;
 import org.briarproject.bramble.api.keyagreement.TransportDescriptor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.BluetoothConstants;
+import org.briarproject.bramble.api.plugin.LanTcpConstants;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -19,7 +22,9 @@ import org.briarproject.bramble.api.record.RecordWriterFactory;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
@@ -28,8 +33,10 @@ import java.util.logging.Logger;

 import javax.annotation.Nullable;

+import static java.util.Arrays.asList;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.CONNECTION_TIMEOUT;
 import static org.briarproject.bramble.util.LogUtils.logException;

@@ -41,7 +48,10 @@ class KeyAgreementConnector {
 	}

 	private static final Logger LOG =
-			Logger.getLogger(KeyAgreementConnector.class.getName());
+			getLogger(KeyAgreementConnector.class.getName());
+
+	private static final List<TransportId> PREFERRED_TRANSPORTS =
+			asList(BluetoothConstants.ID, LanTcpConstants.ID);

 	private final Callbacks callbacks;
 	private final KeyAgreementCrypto keyAgreementCrypto;
@@ -105,24 +115,35 @@ class KeyAgreementConnector {
 		this.alice = alice;
 		aliceLatch.countDown();

-		// Start connecting over supported transports
+		// Start connecting over supported transports in order of preference
 		if (LOG.isLoggable(INFO)) {
 			LOG.info("Starting outgoing BQP connections as "
 					+ (alice ? "Alice" : "Bob"));
 		}
+		Map<TransportId, TransportDescriptor> descriptors = new HashMap<>();
 		for (TransportDescriptor d : remotePayload.getTransportDescriptors()) {
-			Plugin p = pluginManager.getPlugin(d.getId());
-			if (p instanceof DuplexPlugin) {
+			descriptors.put(d.getId(), d);
+		}
+		List<Pair<DuplexPlugin, BdfList>> transports = new ArrayList<>();
+		for (TransportId id : PREFERRED_TRANSPORTS) {
+			TransportDescriptor d = descriptors.get(id);
+			Plugin p = pluginManager.getPlugin(id);
+			if (d != null && p instanceof DuplexPlugin) {
 				if (LOG.isLoggable(INFO))
-					LOG.info("Connecting via " + d.getId());
-				DuplexPlugin plugin = (DuplexPlugin) p;
-				byte[] commitment = remotePayload.getCommitment();
-				BdfList descriptor = d.getDescriptor();
-				connectionChooser.submit(new ReadableTask(
-						new ConnectorTask(plugin, commitment, descriptor)));
+					LOG.info("Connecting via " + id);
+				transports.add(new Pair<>((DuplexPlugin) p, d.getDescriptor()));
 			}
 		}

+		// TODO: If we don't have any transports in common with the peer,
+		//  warn the user and give up (#1224)
+
+		if (!transports.isEmpty()) {
+			byte[] commitment = remotePayload.getCommitment();
+			connectionChooser.submit(new ReadableTask(new ConnectorTask(
+					transports, commitment)));
+		}
+
 		// Get chosen connection
 		try {
 			KeyAgreementConnection chosen =
@@ -148,15 +169,13 @@ class KeyAgreementConnector {

 	private class ConnectorTask implements Callable<KeyAgreementConnection> {

+		private final List<Pair<DuplexPlugin, BdfList>> transports;
 		private final byte[] commitment;
-		private final BdfList descriptor;
-		private final DuplexPlugin plugin;

-		private ConnectorTask(DuplexPlugin plugin, byte[] commitment,
-				BdfList descriptor) {
-			this.plugin = plugin;
+		private ConnectorTask(List<Pair<DuplexPlugin, BdfList>> transports,
+				byte[] commitment) {
+			this.transports = transports;
 			this.commitment = commitment;
-			this.descriptor = descriptor;
 		}

 		@Nullable
@@ -164,13 +183,18 @@ class KeyAgreementConnector {
 		public KeyAgreementConnection call() throws Exception {
 			// Repeat attempts until we connect, get stopped, or get interrupted
 			while (!stopped) {
-				DuplexTransportConnection conn =
-						plugin.createKeyAgreementConnection(commitment,
-								descriptor);
-				if (conn != null) {
-					if (LOG.isLoggable(INFO))
-						LOG.info(plugin.getId() + ": Outgoing connection");
-					return new KeyAgreementConnection(conn, plugin.getId());
+				for (Pair<DuplexPlugin, BdfList> pair : transports) {
+					if (stopped) return null;
+					DuplexPlugin plugin = pair.getFirst();
+					BdfList descriptor = pair.getSecond();
+					DuplexTransportConnection conn =
+							plugin.createKeyAgreementConnection(commitment,
+									descriptor);
+					if (conn != null) {
+						if (LOG.isLoggable(INFO))
+							LOG.info(plugin.getId() + ": Outgoing connection");
+						return new KeyAgreementConnection(conn, plugin.getId());
+					}
 				}
 				// Wait 2s before retry (to circumvent transient failures)
 				Thread.sleep(2000);
@@ -34,12 +34,12 @@ class KeyAgreementTransport {
 			Logger.getLogger(KeyAgreementTransport.class.getName());

 	// Accept records with current protocol version, known record type
-	private static Predicate<Record> ACCEPT = r ->
+	private static final Predicate<Record> ACCEPT = r ->
 			r.getProtocolVersion() == PROTOCOL_VERSION &&
 					isKnownRecordType(r.getRecordType());

 	// Ignore records with current protocol version, unknown record type
-	private static Predicate<Record> IGNORE = r ->
+	private static final Predicate<Record> IGNORE = r ->
 			r.getProtocolVersion() == PROTOCOL_VERSION &&
 					!isKnownRecordType(r.getRecordType());

@@ -53,6 +53,7 @@ import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.plugin.Plugin.PREF_PLUGIN_ENABLE;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
 import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
@@ -354,6 +355,10 @@ class PluginManagerImpl implements PluginManager, Service {
 				} else if (oldState == ACTIVE) {
 					eventBus.broadcast(new TransportInactiveEvent(id));
 				}
+			} else if (newState == DISABLED) {
+				// Broadcast an event even though the state hasn't changed, as
+				// the reasons for the plugin being disabled may have changed
+				eventBus.broadcast(new TransportStateEvent(id, newState));
 			}
 		}

@@ -0,0 +1,633 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.Multiset;
+import org.briarproject.bramble.api.Pair;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStoppedListeningEvent;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.PluginException;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.properties.event.RemoteTransportPropertiesUpdatedEvent;
+import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
+import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
+
+import java.io.IOException;
+import java.security.SecureRandom;
+import java.util.Collection;
+import java.util.UUID;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_ADDRESS_IS_REFLECTED;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_EVER_CONNECTED;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_PLUGIN_ENABLE;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_ADDRESS_IS_REFLECTED;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_EVER_CONNECTED;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_UUID;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.UUID_BYTES;
+import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
+import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.REFLECTED_PROPERTY_PREFIX;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+import static org.briarproject.bramble.util.StringUtils.macToBytes;
+import static org.briarproject.bramble.util.StringUtils.macToString;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+abstract class AbstractBluetoothPlugin<S, SS> implements BluetoothPlugin,
+		EventListener {
+
+	private static final Logger LOG =
+			getLogger(AbstractBluetoothPlugin.class.getName());
+
+	private final BluetoothConnectionLimiter connectionLimiter;
+	final BluetoothConnectionFactory<S> connectionFactory;
+
+	private final Executor ioExecutor, wakefulIoExecutor;
+	private final SecureRandom secureRandom;
+	private final Backoff backoff;
+	private final PluginCallback callback;
+	private final int maxLatency, maxIdleTime;
+	private final AtomicBoolean used = new AtomicBoolean(false);
+	private final AtomicBoolean everConnected = new AtomicBoolean(false);
+
+	protected final PluginState state = new PluginState();
+	protected final Semaphore discoverSemaphore = new Semaphore(1);
+
+	private volatile String contactConnectionsUuid = null;
+
+	abstract void initialiseAdapter() throws IOException;
+
+	abstract boolean isAdapterEnabled();
+
+	/**
+	 * Returns the local Bluetooth address, or null if no valid address can
+	 * be found.
+	 */
+	@Nullable
+	abstract String getBluetoothAddress();
+
+	abstract SS openServerSocket(String uuid) throws IOException;
+
+	abstract void tryToClose(@Nullable SS ss);
+
+	abstract DuplexTransportConnection acceptConnection(SS ss)
+			throws IOException;
+
+	abstract boolean isValidAddress(String address);
+
+	abstract DuplexTransportConnection connectTo(String address, String uuid)
+			throws IOException;
+
+	@Nullable
+	abstract DuplexTransportConnection discoverAndConnect(String uuid);
+
+	AbstractBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
+			BluetoothConnectionFactory<S> connectionFactory,
+			Executor ioExecutor,
+			Executor wakefulIoExecutor,
+			SecureRandom secureRandom,
+			Backoff backoff,
+			PluginCallback callback,
+			int maxLatency,
+			int maxIdleTime) {
+		this.connectionLimiter = connectionLimiter;
+		this.connectionFactory = connectionFactory;
+		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
+		this.secureRandom = secureRandom;
+		this.backoff = backoff;
+		this.callback = callback;
+		this.maxLatency = maxLatency;
+		this.maxIdleTime = maxIdleTime;
+	}
+
+	void onAdapterEnabled() {
+		LOG.info("Bluetooth enabled");
+		// We may not have been able to get the local address before
+		ioExecutor.execute(this::updateProperties);
+		if (getState() == INACTIVE) bind();
+	}
+
+	void onAdapterDisabled() {
+		LOG.info("Bluetooth disabled");
+		connectionLimiter.allConnectionsClosed();
+		// The server socket may not have been closed automatically
+		SS ss = state.clearServerSocket();
+		if (ss != null) {
+			LOG.info("Closing server socket");
+			tryToClose(ss);
+		}
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return maxLatency;
+	}
+
+	@Override
+	public int getMaxIdleTime() {
+		return maxIdleTime;
+	}
+
+	@Override
+	public void start() throws PluginException {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		Settings settings = callback.getSettings();
+		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE,
+				DEFAULT_PREF_PLUGIN_ENABLE);
+		everConnected.set(settings.getBoolean(PREF_EVER_CONNECTED,
+				DEFAULT_PREF_EVER_CONNECTED));
+		state.setStarted(enabledByUser);
+		try {
+			initialiseAdapter();
+		} catch (IOException e) {
+			throw new PluginException(e);
+		}
+		updateProperties();
+		if (enabledByUser && isAdapterEnabled()) bind();
+	}
+
+	private void bind() {
+		ioExecutor.execute(() -> {
+			if (getState() != INACTIVE) return;
+			// Bind a server socket to accept connections from contacts
+			SS ss;
+			try {
+				ss = openServerSocket(contactConnectionsUuid);
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				return;
+			}
+			if (!state.setServerSocket(ss)) {
+				LOG.info("Closing redundant server socket");
+				tryToClose(ss);
+				return;
+			}
+			backoff.reset();
+			acceptContactConnections(ss);
+		});
+	}
+
+	private void updateProperties() {
+		TransportProperties p = callback.getLocalProperties();
+		String address = p.get(PROP_ADDRESS);
+		String uuid = p.get(PROP_UUID);
+		Settings s = callback.getSettings();
+		boolean isReflected = s.getBoolean(PREF_ADDRESS_IS_REFLECTED,
+				DEFAULT_PREF_ADDRESS_IS_REFLECTED);
+		boolean changed = false;
+		if (address == null || isReflected) {
+			address = getBluetoothAddress();
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Local address " + scrubMacAddress(address));
+			}
+			if (address == null) {
+				if (everConnected.get()) {
+					address = getReflectedAddress();
+					if (LOG.isLoggable(INFO)) {
+						LOG.info("Reflected address " +
+								scrubMacAddress(address));
+					}
+					if (address != null) {
+						changed = true;
+						isReflected = true;
+					}
+				}
+			} else {
+				changed = true;
+				isReflected = false;
+			}
+		}
+		if (uuid == null) {
+			byte[] random = new byte[UUID_BYTES];
+			secureRandom.nextBytes(random);
+			uuid = UUID.nameUUIDFromBytes(random).toString();
+			changed = true;
+		}
+		contactConnectionsUuid = uuid;
+		if (changed) {
+			p = new TransportProperties();
+			// If we previously used a reflected address and there's no longer
+			// a reflected address with enough votes to be used, we'll continue
+			// to use the old reflected address until there's a new winner
+			if (address != null) p.put(PROP_ADDRESS, address);
+			p.put(PROP_UUID, uuid);
+			callback.mergeLocalProperties(p);
+			s = new Settings();
+			s.putBoolean(PREF_ADDRESS_IS_REFLECTED, isReflected);
+			callback.mergeSettings(s);
+		}
+	}
+
+	@Nullable
+	private String getReflectedAddress() {
+		// Count the number of votes for each reflected address
+		String key = REFLECTED_PROPERTY_PREFIX + PROP_ADDRESS;
+		Multiset<String> votes = new Multiset<>();
+		for (TransportProperties p : callback.getRemoteProperties()) {
+			String address = p.get(key);
+			if (address != null && isValidAddress(address)) votes.add(address);
+		}
+		// If an address gets more than half of the votes, accept it
+		int total = votes.getTotal();
+		for (String address : votes.keySet()) {
+			if (votes.getCount(address) * 2 > total) return address;
+		}
+		return null;
+	}
+
+	private void acceptContactConnections(SS ss) {
+		while (true) {
+			DuplexTransportConnection conn;
+			try {
+				conn = acceptConnection(ss);
+			} catch (IOException e) {
+				// This is expected when the server socket is closed
+				LOG.info("Server socket closed");
+				state.clearServerSocket();
+				return;
+			}
+			LOG.info("Connection received");
+			connectionLimiter.connectionOpened(conn);
+			backoff.reset();
+			setEverConnected();
+			callback.handleConnection(conn);
+		}
+	}
+
+	private void setEverConnected() {
+		if (!everConnected.getAndSet(true)) {
+			ioExecutor.execute(() -> {
+				Settings s = new Settings();
+				s.putBoolean(PREF_EVER_CONNECTED, true);
+				callback.mergeSettings(s);
+				// Contacts may already have sent a reflected address
+				updateProperties();
+			});
+		}
+	}
+
+	@Override
+	public void stop() {
+		SS ss = state.setStopped();
+		tryToClose(ss);
+	}
+
+	@Override
+	public State getState() {
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return state.getReasonsDisabled();
+	}
+
+	@Override
+	public boolean shouldPoll() {
+		return true;
+	}
+
+	@Override
+	public int getPollingInterval() {
+		return backoff.getPollingInterval();
+	}
+
+	@Override
+	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
+			properties) {
+		if (getState() != ACTIVE) return;
+		backoff.increment();
+		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
+			connect(p.getFirst(), p.getSecond());
+		}
+	}
+
+	private void connect(TransportProperties p, ConnectionHandler h) {
+		String address = p.get(PROP_ADDRESS);
+		if (isNullOrEmpty(address)) return;
+		String uuid = p.get(PROP_UUID);
+		if (isNullOrEmpty(uuid)) return;
+		wakefulIoExecutor.execute(() -> {
+			DuplexTransportConnection d = createConnection(p);
+			if (d != null) {
+				backoff.reset();
+				setEverConnected();
+				h.handleConnection(d);
+			}
+		});
+	}
+
+	@Nullable
+	private DuplexTransportConnection connect(String address, String uuid) {
+		// Validate the address
+		if (!isValidAddress(address)) {
+			if (LOG.isLoggable(WARNING))
+				// Not scrubbing here to be able to figure out the problem
+				LOG.warning("Invalid address " + address);
+			return null;
+		}
+		// Validate the UUID
+		try {
+			//noinspection ResultOfMethodCallIgnored
+			UUID.fromString(uuid);
+		} catch (IllegalArgumentException e) {
+			if (LOG.isLoggable(WARNING)) LOG.warning("Invalid UUID " + uuid);
+			return null;
+		}
+		if (LOG.isLoggable(INFO))
+			LOG.info("Connecting to " + scrubMacAddress(address));
+		try {
+			DuplexTransportConnection conn = connectTo(address, uuid);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Connected to " + scrubMacAddress(address));
+			return conn;
+		} catch (IOException e) {
+			if (LOG.isLoggable(INFO))
+				LOG.info("Could not connect to " + scrubMacAddress(address));
+			return null;
+		}
+	}
+
+	@Override
+	public DuplexTransportConnection createConnection(TransportProperties p) {
+		if (getState() != ACTIVE) return null;
+		if (!connectionLimiter.canOpenContactConnection()) return null;
+		String address = p.get(PROP_ADDRESS);
+		if (isNullOrEmpty(address)) return null;
+		String uuid = p.get(PROP_UUID);
+		if (isNullOrEmpty(uuid)) return null;
+		DuplexTransportConnection conn = connect(address, uuid);
+		if (conn != null) connectionLimiter.connectionOpened(conn);
+		return conn;
+	}
+
+	@Override
+	public boolean supportsKeyAgreement() {
+		return true;
+	}
+
+	@Override
+	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
+		if (getState() != ACTIVE) return null;
+		// No truncation necessary because COMMIT_LENGTH = 16
+		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
+		if (LOG.isLoggable(INFO)) LOG.info("Key agreement UUID " + uuid);
+		// Bind a server socket for receiving key agreement connections
+		SS ss;
+		try {
+			ss = openServerSocket(uuid);
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		}
+		if (getState() != ACTIVE) {
+			tryToClose(ss);
+			return null;
+		}
+		BdfList descriptor = new BdfList();
+		descriptor.add(TRANSPORT_ID_BLUETOOTH);
+		String address = getBluetoothAddress();
+		if (address != null) descriptor.add(macToBytes(address));
+		return new BluetoothKeyAgreementListener(descriptor, ss);
+	}
+
+	@Override
+	public DuplexTransportConnection createKeyAgreementConnection(
+			byte[] commitment, BdfList descriptor) {
+		if (getState() != ACTIVE) return null;
+		// No truncation necessary because COMMIT_LENGTH = 16
+		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
+		DuplexTransportConnection conn;
+		if (descriptor.size() == 1) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Discovering address for key agreement UUID " +
+						uuid);
+			}
+			conn = discoverAndConnect(uuid);
+		} else {
+			String address;
+			try {
+				address = parseAddress(descriptor);
+			} catch (FormatException e) {
+				LOG.info("Invalid address in key agreement descriptor");
+				return null;
+			}
+			if (LOG.isLoggable(INFO))
+				LOG.info("Connecting to key agreement UUID " + uuid);
+			conn = connect(address, uuid);
+		}
+		if (conn != null) {
+			connectionLimiter.connectionOpened(conn);
+			setEverConnected();
+		}
+		return conn;
+	}
+
+	private String parseAddress(BdfList descriptor) throws FormatException {
+		byte[] mac = descriptor.getRaw(1);
+		if (mac.length != 6) throw new FormatException();
+		return macToString(mac);
+	}
+
+	@Override
+	public boolean isDiscovering() {
+		return discoverSemaphore.availablePermits() == 0;
+	}
+
+	@Override
+	public void disablePolling() {
+		connectionLimiter.startLimiting();
+	}
+
+	@Override
+	public void enablePolling() {
+		connectionLimiter.endLimiting();
+	}
+
+	@Override
+	public DuplexTransportConnection discoverAndConnectForSetup(String uuid) {
+		DuplexTransportConnection conn = discoverAndConnect(uuid);
+		if (conn != null) {
+			connectionLimiter.connectionOpened(conn);
+			setEverConnected();
+		}
+		return conn;
+	}
+
+	@Override
+	public boolean supportsRendezvous() {
+		return false;
+	}
+
+	@Override
+	public RendezvousEndpoint createRendezvousEndpoint(KeyMaterialSource k,
+			boolean alice, ConnectionHandler incoming) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof SettingsUpdatedEvent) {
+			SettingsUpdatedEvent s = (SettingsUpdatedEvent) e;
+			if (s.getNamespace().equals(ID.getString()))
+				ioExecutor.execute(() -> onSettingsUpdated(s.getSettings()));
+		} else if (e instanceof KeyAgreementListeningEvent) {
+			connectionLimiter.startLimiting();
+		} else if (e instanceof KeyAgreementStoppedListeningEvent) {
+			connectionLimiter.endLimiting();
+		} else if (e instanceof RemoteTransportPropertiesUpdatedEvent) {
+			RemoteTransportPropertiesUpdatedEvent r =
+					(RemoteTransportPropertiesUpdatedEvent) e;
+			if (r.getTransportId().equals(ID)) {
+				ioExecutor.execute(this::updateProperties);
+			}
+		}
+	}
+
+	@IoExecutor
+	private void onSettingsUpdated(Settings settings) {
+		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE,
+				DEFAULT_PREF_PLUGIN_ENABLE);
+		SS ss = state.setEnabledByUser(enabledByUser);
+		State s = getState();
+		if (ss != null) {
+			LOG.info("Disabled by user, closing server socket");
+			tryToClose(ss);
+		} else if (s == INACTIVE) {
+			if (isAdapterEnabled()) {
+				LOG.info("Enabled by user, opening server socket");
+				bind();
+			} else {
+				LOG.info("Enabled by user but adapter is disabled");
+			}
+		}
+	}
+
+	private class BluetoothKeyAgreementListener extends KeyAgreementListener {
+
+		private final SS ss;
+
+		private BluetoothKeyAgreementListener(BdfList descriptor, SS ss) {
+			super(descriptor);
+			this.ss = ss;
+		}
+
+		@Override
+		public KeyAgreementConnection accept() throws IOException {
+			DuplexTransportConnection conn = acceptConnection(ss);
+			if (LOG.isLoggable(INFO)) LOG.info(ID + ": Incoming connection");
+			connectionLimiter.connectionOpened(conn);
+			return new KeyAgreementConnection(conn, ID);
+		}
+
+		@Override
+		public void close() {
+			tryToClose(ss);
+		}
+	}
+
+	@ThreadSafe
+	@NotNullByDefault
+	private class PluginState {
+
+		@GuardedBy("this")
+		private boolean started = false,
+				stopped = false,
+				enabledByUser = false;
+
+		@GuardedBy("this")
+		@Nullable
+		private SS serverSocket = null;
+
+		private synchronized void setStarted(boolean enabledByUser) {
+			started = true;
+			this.enabledByUser = enabledByUser;
+			callback.pluginStateChanged(getState());
+		}
+
+		@Nullable
+		private synchronized SS setStopped() {
+			stopped = true;
+			SS ss = serverSocket;
+			serverSocket = null;
+			callback.pluginStateChanged(getState());
+			return ss;
+		}
+
+		@Nullable
+		private synchronized SS setEnabledByUser(boolean enabledByUser) {
+			this.enabledByUser = enabledByUser;
+			SS ss = null;
+			if (!enabledByUser) {
+				ss = serverSocket;
+				serverSocket = null;
+			}
+			callback.pluginStateChanged(getState());
+			return ss;
+		}
+
+		private synchronized boolean setServerSocket(SS ss) {
+			if (stopped || serverSocket != null) return false;
+			serverSocket = ss;
+			callback.pluginStateChanged(getState());
+			return true;
+		}
+
+		@Nullable
+		private synchronized SS clearServerSocket() {
+			SS ss = serverSocket;
+			serverSocket = null;
+			callback.pluginStateChanged(getState());
+			return ss;
+		}
+
+		private synchronized State getState() {
+			if (!started || stopped) return STARTING_STOPPING;
+			if (!enabledByUser) return DISABLED;
+			return serverSocket == null ? INACTIVE : ACTIVE;
+		}
+
+		private synchronized int getReasonsDisabled() {
+			return getState() == DISABLED ? REASON_USER : 0;
+		}
+	}
+}
@@ -7,14 +7,15 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 interface BluetoothConnectionLimiter {

 	/**
-	 * Informs the limiter that key agreement has started.
+	 * Tells the limiter to not allow regular polling connections (because we
+	 * are about to do key agreement, or connect via BT for setup).
 	 */
-	void keyAgreementStarted();
+	void startLimiting();

 	/**
-	 * Informs the limiter that key agreement has ended.
+	 * Tells the limiter to no longer limit regular polling connections.
 	 */
-	void keyAgreementEnded();
+	void endLimiting();

 	/**
 	 * Returns true if a contact connection can be opened. This method does not
@@ -30,34 +30,37 @@ class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 	private final List<DuplexTransportConnection> connections =
 			new LinkedList<>();
 	@GuardedBy("lock")
-	private boolean keyAgreementInProgress = false;
+	private int limitingInProgress = 0;

 	BluetoothConnectionLimiterImpl(EventBus eventBus) {
 		this.eventBus = eventBus;
 	}

 	@Override
-	public void keyAgreementStarted() {
+	public void startLimiting() {
 		synchronized (lock) {
-			keyAgreementInProgress = true;
+			limitingInProgress++;
 		}
-		LOG.info("Key agreement started");
+		LOG.info("Limiting started");
 		eventBus.broadcast(new CloseSyncConnectionsEvent(ID));
 	}

 	@Override
-	public void keyAgreementEnded() {
+	public void endLimiting() {
 		synchronized (lock) {
-			keyAgreementInProgress = false;
+			limitingInProgress--;
+			if (limitingInProgress < 0) {
+				throw new IllegalStateException();
+			}
 		}
-		LOG.info("Key agreement ended");
+		LOG.info("Limiting ended");
 	}

 	@Override
 	public boolean canOpenContactConnection() {
 		synchronized (lock) {
-			if (keyAgreementInProgress) {
-				LOG.info("Can't open contact connection during key agreement");
+			if (limitingInProgress > 0) {
+				LOG.info("Can't open contact connection while limiting");
 				return false;
 			} else {
 				LOG.info("Can open contact connection");
@@ -1,621 +1,22 @@
 package org.briarproject.bramble.plugin.bluetooth;

-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.Multiset;
-import org.briarproject.bramble.api.Pair;
-import org.briarproject.bramble.api.data.BdfList;
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventListener;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStoppedListeningEvent;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.ConnectionHandler;
-import org.briarproject.bramble.api.plugin.PluginCallback;
-import org.briarproject.bramble.api.plugin.PluginException;
-import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.plugin.event.BluetoothEnabledEvent;
-import org.briarproject.bramble.api.plugin.event.DisableBluetoothEvent;
-import org.briarproject.bramble.api.plugin.event.EnableBluetoothEvent;
-import org.briarproject.bramble.api.properties.TransportProperties;
-import org.briarproject.bramble.api.properties.event.RemoteTransportPropertiesUpdatedEvent;
-import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
-import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
-import org.briarproject.bramble.api.settings.Settings;
-import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
-
-import java.io.IOException;
-import java.security.SecureRandom;
-import java.util.Collection;
-import java.util.UUID;
-import java.util.concurrent.Executor;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.logging.Logger;

 import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;

-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_ADDRESS_IS_REFLECTED;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_EVER_CONNECTED;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_PLUGIN_ENABLE;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_ADDRESS_IS_REFLECTED;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_EVER_CONNECTED;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_UUID;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.UUID_BYTES;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
-import static org.briarproject.bramble.api.properties.TransportPropertyConstants.REFLECTED_PROPERTY_PREFIX;
-import static org.briarproject.bramble.util.LogUtils.logException;
-import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
-import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
-import static org.briarproject.bramble.util.StringUtils.macToBytes;
-import static org.briarproject.bramble.util.StringUtils.macToString;
+@NotNullByDefault
+public interface BluetoothPlugin extends DuplexPlugin {

-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-abstract class BluetoothPlugin<S, SS> implements DuplexPlugin, EventListener {
+	boolean isDiscovering();

-	private static final Logger LOG =
-			getLogger(BluetoothPlugin.class.getName());
+	void disablePolling();

-	final BluetoothConnectionLimiter connectionLimiter;
-	final BluetoothConnectionFactory<S> connectionFactory;
-
-	private final Executor ioExecutor, wakefulIoExecutor;
-	private final SecureRandom secureRandom;
-	private final Backoff backoff;
-	private final PluginCallback callback;
-	private final int maxLatency, maxIdleTime;
-	private final AtomicBoolean used = new AtomicBoolean(false);
-	private final AtomicBoolean everConnected = new AtomicBoolean(false);
-
-	protected final PluginState state = new PluginState();
-
-	private volatile String contactConnectionsUuid = null;
-
-	abstract void initialiseAdapter() throws IOException;
-
-	abstract boolean isAdapterEnabled();
-
-	abstract void enableAdapter();
-
-	abstract void disableAdapterIfEnabledByUs();
-
-	abstract void setEnabledByUs();
-
-	/**
-	 * Returns the local Bluetooth address, or null if no valid address can
-	 * be found.
-	 */
-	@Nullable
-	abstract String getBluetoothAddress();
-
-	abstract SS openServerSocket(String uuid) throws IOException;
-
-	abstract void tryToClose(@Nullable SS ss);
-
-	abstract DuplexTransportConnection acceptConnection(SS ss)
-			throws IOException;
-
-	abstract boolean isValidAddress(String address);
-
-	abstract DuplexTransportConnection connectTo(String address, String uuid)
-			throws IOException;
+	void enablePolling();

 	@Nullable
-	abstract DuplexTransportConnection discoverAndConnect(String uuid);
+	DuplexTransportConnection discoverAndConnectForSetup(String uuid);

-	BluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
-			BluetoothConnectionFactory<S> connectionFactory,
-			Executor ioExecutor,
-			Executor wakefulIoExecutor,
-			SecureRandom secureRandom,
-			Backoff backoff,
-			PluginCallback callback,
-			int maxLatency,
-			int maxIdleTime) {
-		this.connectionLimiter = connectionLimiter;
-		this.connectionFactory = connectionFactory;
-		this.ioExecutor = ioExecutor;
-		this.wakefulIoExecutor = wakefulIoExecutor;
-		this.secureRandom = secureRandom;
-		this.backoff = backoff;
-		this.callback = callback;
-		this.maxLatency = maxLatency;
-		this.maxIdleTime = maxIdleTime;
-	}
-
-	void onAdapterEnabled() {
-		LOG.info("Bluetooth enabled");
-		// We may not have been able to get the local address before
-		ioExecutor.execute(this::updateProperties);
-		if (getState() == INACTIVE) bind();
-	}
-
-	void onAdapterDisabled() {
-		LOG.info("Bluetooth disabled");
-		connectionLimiter.allConnectionsClosed();
-		// The server socket may not have been closed automatically
-		SS ss = state.clearServerSocket();
-		if (ss != null) {
-			LOG.info("Closing server socket");
-			tryToClose(ss);
-		}
-	}
-
-	@Override
-	public TransportId getId() {
-		return ID;
-	}
-
-	@Override
-	public int getMaxLatency() {
-		return maxLatency;
-	}
-
-	@Override
-	public int getMaxIdleTime() {
-		return maxIdleTime;
-	}
-
-	@Override
-	public void start() throws PluginException {
-		if (used.getAndSet(true)) throw new IllegalStateException();
-		Settings settings = callback.getSettings();
-		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE,
-				DEFAULT_PREF_PLUGIN_ENABLE);
-		everConnected.set(settings.getBoolean(PREF_EVER_CONNECTED,
-				DEFAULT_PREF_EVER_CONNECTED));
-		state.setStarted(enabledByUser);
-		try {
-			initialiseAdapter();
-		} catch (IOException e) {
-			throw new PluginException(e);
-		}
-		updateProperties();
-		if (enabledByUser) {
-			if (isAdapterEnabled()) bind();
-			else enableAdapter();
-		}
-	}
-
-	private void bind() {
-		ioExecutor.execute(() -> {
-			if (getState() != INACTIVE) return;
-			// Bind a server socket to accept connections from contacts
-			SS ss;
-			try {
-				ss = openServerSocket(contactConnectionsUuid);
-			} catch (IOException e) {
-				logException(LOG, WARNING, e);
-				return;
-			}
-			if (!state.setServerSocket(ss)) {
-				LOG.info("Closing redundant server socket");
-				tryToClose(ss);
-				return;
-			}
-			backoff.reset();
-			acceptContactConnections(ss);
-		});
-	}
-
-	private void updateProperties() {
-		TransportProperties p = callback.getLocalProperties();
-		String address = p.get(PROP_ADDRESS);
-		String uuid = p.get(PROP_UUID);
-		Settings s = callback.getSettings();
-		boolean isReflected = s.getBoolean(PREF_ADDRESS_IS_REFLECTED,
-				DEFAULT_PREF_ADDRESS_IS_REFLECTED);
-		boolean changed = false;
-		if (address == null || isReflected) {
-			address = getBluetoothAddress();
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Local address " + scrubMacAddress(address));
-			}
-			if (address == null) {
-				if (everConnected.get()) {
-					address = getReflectedAddress();
-					if (LOG.isLoggable(INFO)) {
-						LOG.info("Reflected address " +
-								scrubMacAddress(address));
-					}
-					if (address != null) {
-						changed = true;
-						isReflected = true;
-					}
-				}
-			} else {
-				changed = true;
-				isReflected = false;
-			}
-		}
-		if (uuid == null) {
-			byte[] random = new byte[UUID_BYTES];
-			secureRandom.nextBytes(random);
-			uuid = UUID.nameUUIDFromBytes(random).toString();
-			changed = true;
-		}
-		contactConnectionsUuid = uuid;
-		if (changed) {
-			p = new TransportProperties();
-			// If we previously used a reflected address and there's no longer
-			// a reflected address with enough votes to be used, we'll continue
-			// to use the old reflected address until there's a new winner
-			if (address != null) p.put(PROP_ADDRESS, address);
-			p.put(PROP_UUID, uuid);
-			callback.mergeLocalProperties(p);
-			s = new Settings();
-			s.putBoolean(PREF_ADDRESS_IS_REFLECTED, isReflected);
-			callback.mergeSettings(s);
-		}
-	}
-
-	@Nullable
-	private String getReflectedAddress() {
-		// Count the number of votes for each reflected address
-		String key = REFLECTED_PROPERTY_PREFIX + PROP_ADDRESS;
-		Multiset<String> votes = new Multiset<>();
-		for (TransportProperties p : callback.getRemoteProperties()) {
-			String address = p.get(key);
-			if (address != null && isValidAddress(address)) votes.add(address);
-		}
-		// If an address gets more than half of the votes, accept it
-		int total = votes.getTotal();
-		for (String address : votes.keySet()) {
-			if (votes.getCount(address) * 2 > total) return address;
-		}
-		return null;
-	}
-
-	private void acceptContactConnections(SS ss) {
-		while (true) {
-			DuplexTransportConnection conn;
-			try {
-				conn = acceptConnection(ss);
-			} catch (IOException e) {
-				// This is expected when the server socket is closed
-				LOG.info("Server socket closed");
-				state.clearServerSocket();
-				return;
-			}
-			LOG.info("Connection received");
-			connectionLimiter.connectionOpened(conn);
-			backoff.reset();
-			setEverConnected();
-			callback.handleConnection(conn);
-		}
-	}
-
-	private void setEverConnected() {
-		if (!everConnected.getAndSet(true)) {
-			ioExecutor.execute(() -> {
-				Settings s = new Settings();
-				s.putBoolean(PREF_EVER_CONNECTED, true);
-				callback.mergeSettings(s);
-				// Contacts may already have sent a reflected address
-				updateProperties();
-			});
-		}
-	}
-
-	@Override
-	public void stop() {
-		SS ss = state.setStopped();
-		tryToClose(ss);
-		disableAdapterIfEnabledByUs();
-	}
-
-	@Override
-	public State getState() {
-		return state.getState();
-	}
-
-	@Override
-	public int getReasonsDisabled() {
-		return state.getReasonsDisabled();
-	}
-
-	@Override
-	public boolean shouldPoll() {
-		return true;
-	}
-
-	@Override
-	public int getPollingInterval() {
-		return backoff.getPollingInterval();
-	}
-
-	@Override
-	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
-			properties) {
-		if (getState() != ACTIVE) return;
-		backoff.increment();
-		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
-			connect(p.getFirst(), p.getSecond());
-		}
-	}
-
-	private void connect(TransportProperties p, ConnectionHandler h) {
-		String address = p.get(PROP_ADDRESS);
-		if (isNullOrEmpty(address)) return;
-		String uuid = p.get(PROP_UUID);
-		if (isNullOrEmpty(uuid)) return;
-		wakefulIoExecutor.execute(() -> {
-			DuplexTransportConnection d = createConnection(p);
-			if (d != null) {
-				backoff.reset();
-				setEverConnected();
-				h.handleConnection(d);
-			}
-		});
-	}
-
-	@Nullable
-	private DuplexTransportConnection connect(String address, String uuid) {
-		// Validate the address
-		if (!isValidAddress(address)) {
-			if (LOG.isLoggable(WARNING))
-				// Not scrubbing here to be able to figure out the problem
-				LOG.warning("Invalid address " + address);
-			return null;
-		}
-		// Validate the UUID
-		try {
-			//noinspection ResultOfMethodCallIgnored
-			UUID.fromString(uuid);
-		} catch (IllegalArgumentException e) {
-			if (LOG.isLoggable(WARNING)) LOG.warning("Invalid UUID " + uuid);
-			return null;
-		}
-		if (LOG.isLoggable(INFO))
-			LOG.info("Connecting to " + scrubMacAddress(address));
-		try {
-			DuplexTransportConnection conn = connectTo(address, uuid);
-			if (LOG.isLoggable(INFO))
-				LOG.info("Connected to " + scrubMacAddress(address));
-			return conn;
-		} catch (IOException e) {
-			if (LOG.isLoggable(INFO))
-				LOG.info("Could not connect to " + scrubMacAddress(address));
-			return null;
-		}
-	}
-
-	@Override
-	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (getState() != ACTIVE) return null;
-		if (!connectionLimiter.canOpenContactConnection()) return null;
-		String address = p.get(PROP_ADDRESS);
-		if (isNullOrEmpty(address)) return null;
-		String uuid = p.get(PROP_UUID);
-		if (isNullOrEmpty(uuid)) return null;
-		DuplexTransportConnection conn = connect(address, uuid);
-		if (conn != null) connectionLimiter.connectionOpened(conn);
-		return conn;
-	}
-
-	@Override
-	public boolean supportsKeyAgreement() {
-		return true;
-	}
-
-	@Override
-	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
-		if (getState() != ACTIVE) return null;
-		// No truncation necessary because COMMIT_LENGTH = 16
-		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
-		if (LOG.isLoggable(INFO)) LOG.info("Key agreement UUID " + uuid);
-		// Bind a server socket for receiving key agreement connections
-		SS ss;
-		try {
-			ss = openServerSocket(uuid);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-			return null;
-		}
-		if (getState() != ACTIVE) {
-			tryToClose(ss);
-			return null;
-		}
-		BdfList descriptor = new BdfList();
-		descriptor.add(TRANSPORT_ID_BLUETOOTH);
-		String address = getBluetoothAddress();
-		if (address != null) descriptor.add(macToBytes(address));
-		return new BluetoothKeyAgreementListener(descriptor, ss);
-	}
-
-	@Override
-	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor) {
-		if (getState() != ACTIVE) return null;
-		// No truncation necessary because COMMIT_LENGTH = 16
-		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
-		DuplexTransportConnection conn;
-		if (descriptor.size() == 1) {
-			if (LOG.isLoggable(INFO))
-				LOG.info("Discovering address for key agreement UUID " + uuid);
-			conn = discoverAndConnect(uuid);
-		} else {
-			String address;
-			try {
-				address = parseAddress(descriptor);
-			} catch (FormatException e) {
-				LOG.info("Invalid address in key agreement descriptor");
-				return null;
-			}
-			if (LOG.isLoggable(INFO))
-				LOG.info("Connecting to key agreement UUID " + uuid);
-			conn = connect(address, uuid);
-		}
-		if (conn != null) {
-			connectionLimiter.connectionOpened(conn);
-			setEverConnected();
-		}
-		return conn;
-	}
-
-	private String parseAddress(BdfList descriptor) throws FormatException {
-		byte[] mac = descriptor.getRaw(1);
-		if (mac.length != 6) throw new FormatException();
-		return macToString(mac);
-	}
-
-	@Override
-	public boolean supportsRendezvous() {
-		return false;
-	}
-
-	@Override
-	public RendezvousEndpoint createRendezvousEndpoint(KeyMaterialSource k,
-			boolean alice, ConnectionHandler incoming) {
-		throw new UnsupportedOperationException();
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		if (e instanceof EnableBluetoothEvent) {
-			ioExecutor.execute(this::enableAdapter);
-		} else if (e instanceof DisableBluetoothEvent) {
-			ioExecutor.execute(this::disableAdapterIfEnabledByUs);
-		} else if (e instanceof BluetoothEnabledEvent) {
-			setEnabledByUs();
-		} else if (e instanceof SettingsUpdatedEvent) {
-			SettingsUpdatedEvent s = (SettingsUpdatedEvent) e;
-			if (s.getNamespace().equals(ID.getString()))
-				ioExecutor.execute(() -> onSettingsUpdated(s.getSettings()));
-		} else if (e instanceof KeyAgreementListeningEvent) {
-			ioExecutor.execute(connectionLimiter::keyAgreementStarted);
-		} else if (e instanceof KeyAgreementStoppedListeningEvent) {
-			ioExecutor.execute(connectionLimiter::keyAgreementEnded);
-		} else if (e instanceof RemoteTransportPropertiesUpdatedEvent) {
-			RemoteTransportPropertiesUpdatedEvent r =
-					(RemoteTransportPropertiesUpdatedEvent) e;
-			if (r.getTransportId().equals(ID)) {
-				ioExecutor.execute(this::updateProperties);
-			}
-		}
-	}
-
-	@IoExecutor
-	private void onSettingsUpdated(Settings settings) {
-		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE,
-				DEFAULT_PREF_PLUGIN_ENABLE);
-		SS ss = state.setEnabledByUser(enabledByUser);
-		State s = getState();
-		if (ss != null) {
-			LOG.info("Disabled by user, closing server socket");
-			tryToClose(ss);
-			disableAdapterIfEnabledByUs();
-		} else if (s == INACTIVE) {
-			LOG.info("Enabled by user, opening server socket");
-			if (isAdapterEnabled()) bind();
-			else enableAdapter();
-		}
-	}
-
-	private class BluetoothKeyAgreementListener extends KeyAgreementListener {
-
-		private final SS ss;
-
-		private BluetoothKeyAgreementListener(BdfList descriptor, SS ss) {
-			super(descriptor);
-			this.ss = ss;
-		}
-
-		@Override
-		public KeyAgreementConnection accept() throws IOException {
-			DuplexTransportConnection conn = acceptConnection(ss);
-			if (LOG.isLoggable(INFO)) LOG.info(ID + ": Incoming connection");
-			connectionLimiter.connectionOpened(conn);
-			return new KeyAgreementConnection(conn, ID);
-		}
-
-		@Override
-		public void close() {
-			tryToClose(ss);
-		}
-	}
-
-	@ThreadSafe
-	@NotNullByDefault
-	protected class PluginState {
-
-		@GuardedBy("this")
-		private boolean started = false,
-				stopped = false,
-				enabledByUser = false;
-
-		@GuardedBy("this")
-		@Nullable
-		private SS serverSocket = null;
-
-		synchronized void setStarted(boolean enabledByUser) {
-			started = true;
-			this.enabledByUser = enabledByUser;
-			callback.pluginStateChanged(getState());
-		}
-
-		@Nullable
-		synchronized SS setStopped() {
-			stopped = true;
-			SS ss = serverSocket;
-			serverSocket = null;
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		@Nullable
-		synchronized SS setEnabledByUser(boolean enabledByUser) {
-			this.enabledByUser = enabledByUser;
-			SS ss = null;
-			if (!enabledByUser) {
-				ss = serverSocket;
-				serverSocket = null;
-			}
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		synchronized boolean setServerSocket(SS ss) {
-			if (stopped || serverSocket != null) return false;
-			serverSocket = ss;
-			callback.pluginStateChanged(getState());
-			return true;
-		}
-
-		@Nullable
-		synchronized SS clearServerSocket() {
-			SS ss = serverSocket;
-			serverSocket = null;
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		synchronized State getState() {
-			if (!started || stopped) return STARTING_STOPPING;
-			if (!enabledByUser) return DISABLED;
-			return serverSocket == null ? INACTIVE : ACTIVE;
-		}
-
-		synchronized int getReasonsDisabled() {
-			return getState() == DISABLED ? REASON_USER : 0;
-		}
-	}
+	void stopDiscoverAndConnect();
 }
@@ -132,7 +132,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final CircumventionProvider circumventionProvider;
 	private final ResourceProvider resourceProvider;
 	private final int maxLatency, maxIdleTime, socketTimeout;
-	private final File torDirectory, torFile, geoIpFile, obfs4File, configFile;
+	private final File torDirectory, geoIpFile, configFile;
 	private final File doneFile, cookieFile;
 	private final AtomicBoolean used = new AtomicBoolean(false);

@@ -181,9 +181,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			socketTimeout = Integer.MAX_VALUE;
 		else socketTimeout = maxIdleTime * 2;
 		this.torDirectory = torDirectory;
-		torFile = new File(torDirectory, "tor");
 		geoIpFile = new File(torDirectory, "geoip");
-		obfs4File = new File(torDirectory, "obfs4proxy");
 		configFile = new File(torDirectory, "torrc");
 		doneFile = new File(torDirectory, "done");
 		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
@@ -192,6 +190,14 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				new PoliteExecutor("TorPlugin", ioExecutor, 1);
 	}

+	protected File getTorExecutableFile() {
+		return new File(torDirectory, "tor");
+	}
+
+	protected File getObfs4ExecutableFile() {
+		return new File(torDirectory, "obfs4proxy");
+	}
+
 	@Override
 	public TransportId getId() {
 		return TorConstants.ID;
@@ -224,6 +230,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			LOG.warning("Old auth cookie not deleted");
 		// Start a new Tor process
 		LOG.info("Starting Tor");
+		File torFile = getTorExecutableFile();
 		String torPath = torFile.getAbsolutePath();
 		String configPath = configFile.getAbsolutePath();
 		String pid = String.valueOf(getProcessId());
@@ -322,44 +329,43 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}

 	private void installAssets() throws PluginException {
-		InputStream in = null;
-		OutputStream out = null;
 		try {
 			// The done file may already exist from a previous installation
 			//noinspection ResultOfMethodCallIgnored
 			doneFile.delete();
-			// Unzip the Tor binary to the filesystem
-			in = getTorInputStream();
-			out = new FileOutputStream(torFile);
-			copyAndClose(in, out);
-			// Make the Tor binary executable
-			if (!torFile.setExecutable(true, true)) throw new IOException();
-			// Unzip the GeoIP database to the filesystem
-			in = getGeoIpInputStream();
-			out = new FileOutputStream(geoIpFile);
-			copyAndClose(in, out);
-			// Unzip the Obfs4 proxy to the filesystem
-			in = getObfs4InputStream();
-			out = new FileOutputStream(obfs4File);
-			copyAndClose(in, out);
-			// Make the Obfs4 proxy executable
-			if (!obfs4File.setExecutable(true, true)) throw new IOException();
-			// Copy the config file to the filesystem
-			in = getConfigInputStream();
-			out = new FileOutputStream(configFile);
-			copyAndClose(in, out);
+			installTorExecutable();
+			installObfs4Executable();
+			extract(getGeoIpInputStream(), geoIpFile);
+			extract(getConfigInputStream(), configFile);
 			if (!doneFile.createNewFile())
 				LOG.warning("Failed to create done file");
 		} catch (IOException e) {
-			tryToClose(in, LOG, WARNING);
-			tryToClose(out, LOG, WARNING);
 			throw new PluginException(e);
 		}
 	}

-	private InputStream getTorInputStream() throws IOException {
+	protected void extract(InputStream in, File dest) throws IOException {
+		OutputStream out = new FileOutputStream(dest);
+		copyAndClose(in, out);
+	}
+
+	protected void installTorExecutable() throws IOException {
 		if (LOG.isLoggable(INFO))
 			LOG.info("Installing Tor binary for " + architecture);
+		File torFile = getTorExecutableFile();
+		extract(getTorInputStream(), torFile);
+		if (!torFile.setExecutable(true, true)) throw new IOException();
+	}
+
+	protected void installObfs4Executable() throws IOException {
+		if (LOG.isLoggable(INFO))
+			LOG.info("Installing obfs4proxy binary for " + architecture);
+		File obfs4File = getObfs4ExecutableFile();
+		extract(getObfs4InputStream(), obfs4File);
+		if (!obfs4File.setExecutable(true, true)) throw new IOException();
+	}
+
+	private InputStream getTorInputStream() throws IOException {
 		InputStream in = resourceProvider
 				.getResourceInputStream("tor_" + architecture, ".zip");
 		ZipInputStream zin = new ZipInputStream(in);
@@ -376,8 +382,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}

 	private InputStream getObfs4InputStream() throws IOException {
-		if (LOG.isLoggable(INFO))
-			LOG.info("Installing obfs4proxy binary for " + architecture);
 		InputStream in = resourceProvider
 				.getResourceInputStream("obfs4proxy_" + architecture, ".zip");
 		ZipInputStream zin = new ZipInputStream(in);
@@ -569,6 +573,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (enable) {
 			Collection<String> conf = new ArrayList<>();
 			conf.add("UseBridges 1");
+			File obfs4File = getObfs4ExecutableFile();
 			if (needsMeek) {
 				conf.add("ClientTransportPlugin meek_lite exec " +
 						obfs4File.getAbsolutePath());
@@ -858,6 +863,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			if (!state.isTorRunning()) return;
 			boolean online = status.isConnected();
 			boolean wifi = status.isWifi();
+			boolean ipv6Only = status.isIpv6Only();
 			String country = locationUtils.getCurrentCountry();
 			boolean blocked =
 					circumventionProvider.isTorProbablyBlocked(country);
@@ -874,7 +880,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			boolean automatic = network == PREF_TOR_NETWORK_AUTOMATIC;

 			if (LOG.isLoggable(INFO)) {
-				LOG.info("Online: " + online + ", wifi: " + wifi);
+				LOG.info("Online: " + online + ", wifi: " + wifi
+						+ ", IPv6 only: " + ipv6Only);
 				if (country.isEmpty()) LOG.info("Country code unknown");
 				else LOG.info("Country code: " + country);
 				LOG.info("Charging: " + charging);
@@ -911,7 +918,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 					enableNetwork = true;
 					if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
 							(automatic && bridgesWork)) {
-						if (circumventionProvider.needsMeek(country)) {
+						if (ipv6Only ||
+								circumventionProvider.needsMeek(country)) {
 							LOG.info("Using meek bridges");
 							enableBridges = true;
 							useMeek = true;
@@ -937,6 +945,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				if (enableNetwork) {
 					enableBridges(enableBridges, useMeek);
 					enableConnectionPadding(enableConnectionPadding);
+					useIpv6(ipv6Only);
 				}
 				enableNetwork(enableNetwork);
 			} catch (IOException e) {
@@ -949,6 +958,11 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		controlConnection.setConf("ConnectionPadding", enable ? "1" : "0");
 	}

+	private void useIpv6(boolean ipv6Only) throws IOException {
+		controlConnection.setConf("ClientUseIPv4", ipv6Only ? "0" : "1");
+		controlConnection.setConf("ClientUseIPv6", ipv6Only ? "1" : "0");
+	}
+
 	@ThreadSafe
 	@NotNullByDefault
 	protected class PluginState {
@@ -15,6 +15,9 @@ import org.briarproject.bramble.api.system.Clock;
 import javax.annotation.concurrent.Immutable;

 import static org.briarproject.bramble.api.plugin.TransportId.MAX_TRANSPORT_ID_LENGTH;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_LOCAL;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_TRANSPORT_ID;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_VERSION;
 import static org.briarproject.bramble.util.ValidationUtils.checkLength;
 import static org.briarproject.bramble.util.ValidationUtils.checkSize;

@@ -43,9 +46,9 @@ class TransportPropertyValidator extends BdfMessageValidator {
 		clientHelper.parseAndValidateTransportProperties(dictionary);
 		// Return the metadata
 		BdfDictionary meta = new BdfDictionary();
-		meta.put("transportId", transportId);
-		meta.put("version", version);
-		meta.put("local", false);
+		meta.put(MSG_KEY_TRANSPORT_ID, transportId);
+		meta.put(MSG_KEY_VERSION, version);
+		meta.put(MSG_KEY_LOCAL, false);
 		return new BdfMessageContext(meta);
 	}
 }
@@ -42,6 +42,7 @@ import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedE
 import org.briarproject.bramble.api.rendezvous.event.RendezvousPollEvent;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
 import org.briarproject.bramble.api.system.Wakeful;

 import java.security.GeneralSecurityException;
@@ -68,6 +69,7 @@ import static org.briarproject.bramble.api.contact.PendingContactState.ADDING_CO
 import static org.briarproject.bramble.api.contact.PendingContactState.FAILED;
 import static org.briarproject.bramble.api.contact.PendingContactState.OFFLINE;
 import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNull;
 import static org.briarproject.bramble.rendezvous.RendezvousConstants.POLLING_INTERVAL_MS;
 import static org.briarproject.bramble.rendezvous.RendezvousConstants.RENDEZVOUS_TIMEOUT_MS;
@@ -102,6 +104,8 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			new HashMap<>();
 	@Nullable
 	private KeyPair handshakeKeyPair = null;
+	@Nullable
+	private Cancellable pollTask = null;

 	@Inject
 	RendezvousPollerImpl(@IoExecutor Executor ioExecutor,
@@ -144,8 +148,6 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 		} catch (DbException e) {
 			throw new ServiceException(e);
 		}
-		scheduler.scheduleWithFixedDelay(this::poll, worker,
-				POLLING_INTERVAL_MS, POLLING_INTERVAL_MS, MILLISECONDS);
 	}

 	@EventExecutor
@@ -186,6 +188,12 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			}
 			if (cs.numEndpoints == 0) broadcastState(p.getId(), OFFLINE);
 			else broadcastState(p.getId(), WAITING_FOR_CONNECTION);
+			if (cryptoStates.size() == 1) {
+				LOG.info("Starting poller");
+				requireNull(pollTask);
+				pollTask = scheduler.scheduleWithFixedDelay(this::poll, worker,
+						POLLING_INTERVAL_MS, POLLING_INTERVAL_MS, MILLISECONDS);
+			}
 		} catch (DbException | GeneralSecurityException e) {
 			logException(LOG, WARNING, e);
 		}
@@ -208,6 +216,7 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 	// Worker
 	@Wakeful
 	private void poll() {
+		LOG.info("Polling");
 		removeExpiredPendingContacts();
 		for (PluginState ps : pluginStates.values()) poll(ps);
 	}
@@ -234,6 +243,11 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			RendezvousEndpoint endpoint = ps.endpoints.remove(p);
 			if (endpoint != null) tryToClose(endpoint, LOG, INFO);
 		}
+		if (cryptoStates.isEmpty()) {
+			LOG.info("Stopping poller");
+			requireNonNull(pollTask).cancel();
+			pollTask = null;
+		}
 	}

 	// Worker
@@ -29,6 +29,7 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 import javax.net.SocketFactory;

+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.IoUtils.tryToClose;

@@ -100,11 +101,12 @@ class DevReporterImpl implements DevReporter, EventListener {
 	}

 	@Override
-	public void sendReports() {
+	public int sendReports() {
 		File reportDir = devConfig.getReportDir();
 		File[] reports = reportDir.listFiles();
+		int reportsSent = 0;
 		if (reports == null || reports.length == 0)
-			return; // No reports to send
+			return reportsSent; // No reports to send

 		LOG.info("Sending reports to developers");
 		for (File f : reports) {
@@ -116,13 +118,15 @@ class DevReporterImpl implements DevReporter, EventListener {
 				in = new FileInputStream(f);
 				IoUtils.copyAndClose(in, out);
 				f.delete();
+				reportsSent++;
 			} catch (IOException e) {
 				LOG.log(WARNING, "Failed to send reports", e);
 				tryToClose(out, LOG, WARNING);
 				tryToClose(in, LOG, WARNING);
-				return;
+				return reportsSent;
 			}
 		}
-		LOG.info("Reports sent");
+		if (LOG.isLoggable(INFO)) LOG.info(reportsSent + " report(s) sent");
+		return reportsSent;
 	}
 }
@@ -24,15 +24,21 @@ class StreamReaderFactoryImpl implements StreamReaderFactory {

 	@Override
 	public InputStream createStreamReader(InputStream in, StreamContext ctx) {
-		return new StreamReaderImpl(
-				streamDecrypterFactory.createStreamDecrypter(in, ctx));
+		return new StreamReaderImpl(streamDecrypterFactory
+				.createStreamDecrypter(in, ctx));
 	}

 	@Override
 	public InputStream createContactExchangeStreamReader(InputStream in,
 			SecretKey headerKey) {
-		return new StreamReaderImpl(
-				streamDecrypterFactory.createContactExchangeStreamDecrypter(in,
-						headerKey));
+		return new StreamReaderImpl(streamDecrypterFactory
+				.createContactExchangeStreamDecrypter(in, headerKey));
+	}
+
+	@Override
+	public InputStream createLogStreamReader(InputStream in,
+			SecretKey headerKey) {
+		return new StreamReaderImpl(streamDecrypterFactory
+				.createLogStreamDecrypter(in, headerKey));
 	}
 }
@@ -26,15 +26,21 @@ class StreamWriterFactoryImpl implements StreamWriterFactory {
 	@Override
 	public StreamWriter createStreamWriter(OutputStream out,
 			StreamContext ctx) {
-		return new StreamWriterImpl(
-				streamEncrypterFactory.createStreamEncrypter(out, ctx));
+		return new StreamWriterImpl(streamEncrypterFactory
+				.createStreamEncrypter(out, ctx));
 	}

 	@Override
 	public StreamWriter createContactExchangeStreamWriter(OutputStream out,
 			SecretKey headerKey) {
-		return new StreamWriterImpl(
-				streamEncrypterFactory.createContactExchangeStreamDecrypter(out,
-						headerKey));
+		return new StreamWriterImpl(streamEncrypterFactory
+				.createContactExchangeStreamEncrypter(out, headerKey));
 	}
-}
+
+	@Override
+	public StreamWriter createLogStreamWriter(OutputStream out,
+			SecretKey headerKey) {
+		return new StreamWriterImpl(streamEncrypterFactory
+				.createLogStreamEncrypter(out, headerKey));
+	}
+}
@@ -5,6 +5,5 @@ interface ClientVersioningConstants {
 	// Metadata keys
 	String MSG_KEY_UPDATE_VERSION = "version";
 	String MSG_KEY_LOCAL = "local";
-	String GROUP_KEY_CONTACT_ID = "contactId";
 }

@@ -50,7 +50,6 @@ import static java.util.Collections.emptyList;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
-import static org.briarproject.bramble.versioning.ClientVersioningConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_LOCAL;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_UPDATE_VERSION;

@@ -161,13 +160,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager,
 		db.addGroup(txn, g);
 		db.setGroupVisibility(txn, c.getId(), g.getId(), SHARED);
 		// Attach the contact ID to the group
-		BdfDictionary meta = new BdfDictionary();
-		meta.put(GROUP_KEY_CONTACT_ID, c.getId().getInt());
-		try {
-			clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
-		} catch (FormatException e) {
-			throw new AssertionError(e);
-		}
+		clientHelper.setContactId(txn, g.getId(), c.getId());
 		// Create and store the first local update
 		List<ClientVersion> versions = new ArrayList<>(clients);
 		Collections.sort(versions);
@@ -229,7 +222,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager,
 			Map<ClientMajorVersion, Visibility> after =
 					getVisibilities(newLocalStates, newRemoteStates);
 			// Call hooks for any visibilities that have changed
-			ContactId c = getContactId(txn, m.getGroupId());
+			ContactId c = clientHelper.getContactId(txn, m.getGroupId());
 			if (!before.equals(after)) {
 				Contact contact = db.getContact(txn, c);
 				callVisibilityHooks(txn, contact, before, after);
@@ -521,17 +514,6 @@ class ClientVersioningManagerImpl implements ClientVersioningManager,
 		storeUpdate(txn, g, states, 1);
 	}

-	private ContactId getContactId(Transaction txn, GroupId g)
-			throws DbException {
-		try {
-			BdfDictionary meta =
-					clientHelper.getGroupMetadataAsDictionary(txn, g);
-			return new ContactId(meta.getLong(GROUP_KEY_CONTACT_ID).intValue());
-		} catch (FormatException e) {
-			throw new DbException(e);
-		}
-	}
-
 	private List<ClientState> updateStatesFromRemoteStates(
 			List<ClientState> oldLocalStates, List<ClientState> remoteStates) {
 		Set<ClientMajorVersion> remoteSet = new HashSet<>();
@@ -1,5 +1,10 @@
+Bridge obfs4 37.218.245.14:38224 D9A82D2F9C2F65A18407B1D2B764F130847F8B5D cert=bjRaMrr1BRiAW8IE9U5z27fQaYgOhX1UCmOpg2pFpoMvo6ZgQMzLsaTzzQNTlm7hNcb+Sg iat-mode=0
+Bridge obfs4 85.31.186.26:443 91A6354697E6B02A386312F68D82CF86824D3606 cert=PBwr+S8JTVZo6MPdHnkTwXJPILWADLqfMGoVvhZClMq/Urndyd42BwX9YFJHZnBB3H0XCw iat-mode=0
+Bridge obfs4 193.11.166.194:27015 2D82C2E354D531A68469ADF7F878FA6060C6BACA cert=4TLQPJrTSaDffMK7Nbao6LC7G9OW/NHkUwIdjLSS3KYf0Nv4/nQiiI8dY2TcsQx01NniOg iat-mode=0
+Bridge obfs4 193.11.166.194:27020 86AC7B8D430DAC4117E9F42C9EAED18133863AAF cert=0LDeJH4JzMDtkJJrFphJCiPqKx7loozKN7VNfuukMGfHO0Z8OGdzHVkhVAOfo1mUdv9cMg iat-mode=0
+Bridge obfs4 193.11.166.194:27025 1AE2C08904527FEA90C4C4F8C1083EA59FBC6FAF cert=ItvYZzW5tn6v3G4UnQa6Qz04Npro6e81AP70YujmK/KXwDFPTs3aHXcHp4n8Vt6w/bv8cA iat-mode=0
+Bridge obfs4 209.148.46.65:443 74FAD13168806246602538555B5521A0383A1875 cert=ssH+9rP8dG2NLDN2XuFw63hIO/9MNNinLmxQDpVa+7kTOa9/m+tGWT1SmSYpQ9uTBGa6Hw iat-mode=0
+Bridge obfs4 45.145.95.6:27015 C5B7CD6946FF10C5B3E89691A7D3F2C122D2117C cert=TD7PbUO0/0k6xYHMPW3vJxICfkMZNdkRrb63Zhl5j9dW3iRGiCx0A7mPhe5T2EDzQ35+Zw iat-mode=0
+Bridge obfs4 51.222.13.177:80 5EDAC3B810E12B01F6FD8050D2FD3E277B289A08 cert=2uplIpLQ0q9+0qMFrK5pkaYRDOe460LL9WHBvatgkuRr/SL31wBOEupaMMJ6koRE6Ld0ew iat-mode=0
 Bridge obfs4 78.46.188.239:37356 5A2D2F4158D0453E00C7C176978D3F41D69C45DB cert=3c0SwxpOisbohNxEc4tb875RVW8eOu1opRTVXJhafaKA/PNNtI7ElQIVOVZg1AdL5bxGCw iat-mode=0
-Bridge obfs4 52.15.78.72:9443 02069A3C5362476936B62BA6F5ACC41ABD573A9B cert=ijYG/OKc7kqu2YzKNFfeXN7/BG2BOgfEP2KyYEiGDQthnHbsOiTWHeIG0WJVW+BckzDgKw iat-mode=0
-Bridge obfs4 13.58.29.242:9443 0C58939A77DA6B6B29D4B5236A75865659607AE0 cert=OylWIEHb/ezpq1zWxW0sgKRn+9ARH2eOcQOZ8/Gew+4l+oKOhQ2jUX/Y+FSl61JorXZUWA iat-mode=0
-Bridge obfs4 45.33.37.112:9443 60A609BB4ABE8D46E634AE81ED29ADAB7776B399 cert=t5v19WmNv5Sc2YPNr8RQids365W7MY8zJwQVkOxBjUMFomMWARDzsbYpcWLLcw0J9Gm+BQ iat-mode=0
-Bridge meek_lite 0.0.2.0:2 97700DFE9F483596DDA6264C4D7DF7641E1E39CE url=https://meek.azureedge.net/ front=ajax.aspnetcdn.com
+Bridge meek_lite 192.0.2.2:2 97700DFE9F483596DDA6264C4D7DF7641E1E39CE url=https://meek.azureedge.net/ front=ajax.aspnetcdn.com
@@ -1,18 +1,18 @@
 package org.briarproject.bramble;

-import org.briarproject.bramble.system.DefaultTaskSchedulerModule;
+import org.briarproject.bramble.system.TimeTravelModule;

 public interface BrambleCoreIntegrationTestEagerSingletons
 		extends BrambleCoreEagerSingletons {

-	void inject(DefaultTaskSchedulerModule.EagerSingletons init);
+	void inject(TimeTravelModule.EagerSingletons init);

 	class Helper {

 		public static void injectEagerSingletons(
 				BrambleCoreIntegrationTestEagerSingletons c) {
 			BrambleCoreEagerSingletons.Helper.injectEagerSingletons(c);
-			c.inject(new DefaultTaskSchedulerModule.EagerSingletons());
+			c.inject(new TimeTravelModule.EagerSingletons());
 		}
 	}
 }
@@ -134,7 +134,7 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 					keyStrengthener);
 			will(returnValue(key.getBytes()));
 			oneOf(crypto).isEncryptedWithStrengthenedKey(encryptedKey);
-			will(returnValue(false));
+			will(returnValue(true));
 		}});

 		storeDatabaseKey(keyFile, encryptedKeyHex);
@@ -160,8 +160,9 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 					keyStrengthener);
 			will(returnValue(key.getBytes()));
 			oneOf(crypto).isEncryptedWithStrengthenedKey(encryptedKey);
-			will(returnValue(true));
-			oneOf(crypto).encryptWithPassword(key.getBytes(), password, null);
+			will(returnValue(false));
+			oneOf(crypto).encryptWithPassword(key.getBytes(), password,
+					keyStrengthener);
 			will(returnValue(newEncryptedKey));
 		}});

@@ -261,7 +262,8 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 			oneOf(identityManager).registerIdentity(identity);
 			oneOf(crypto).generateSecretKey();
 			will(returnValue(key));
-			oneOf(crypto).encryptWithPassword(key.getBytes(), password, null);
+			oneOf(crypto).encryptWithPassword(key.getBytes(), password,
+					keyStrengthener);
 			will(returnValue(encryptedKey));
 		}});

@@ -321,8 +323,10 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 			oneOf(crypto).decryptWithPassword(encryptedKey, password,
 					keyStrengthener);
 			will(returnValue(key.getBytes()));
+			oneOf(crypto).isEncryptedWithStrengthenedKey(encryptedKey);
+			will(returnValue(true));
 			oneOf(crypto).encryptWithPassword(key.getBytes(), newPassword,
-					null);
+					keyStrengthener);
 			will(returnValue(newEncryptedKey));
 		}});

@@ -8,18 +8,15 @@ import org.briarproject.bramble.api.contact.PendingContactState;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseComponent;
-import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.transport.KeyManager;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.DbExpectations;
-import org.jmock.Expectations;
 import org.junit.Before;
 import org.junit.Test;

@@ -31,10 +28,6 @@ import static java.util.Collections.singletonList;
 import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.BASE32_LINK_BYTES;
 import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
 import static org.briarproject.bramble.test.TestUtils.getAgreementPrivateKey;
 import static org.briarproject.bramble.test.TestUtils.getAgreementPublicKey;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
@@ -46,7 +39,6 @@ import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.briarproject.bramble.util.StringUtils.getRandomBase32String;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;

 public class ContactManagerImplTest extends BrambleMockTestCase {
@@ -212,75 +204,6 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		assertTrue(contactManager.contactExists(remote.getId(), local));
 	}

-	@Test
-	public void testGetAuthorInfo() throws Exception {
-		Transaction txn = new Transaction(null, true);
-
-		context.checking(new DbExpectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(singletonList(contact)));
-		}});
-
-		AuthorInfo authorInfo =
-				contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNVERIFIED, authorInfo.getStatus());
-		assertEquals(contact.getAlias(), authorInfo.getAlias());
-	}
-
-	@Test
-	public void testGetAuthorInfoTransaction() throws DbException {
-		Transaction txn = new Transaction(null, true);
-
-		// check unknown author
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(emptyList()));
-		}});
-
-		AuthorInfo authorInfo =
-				contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNKNOWN, authorInfo.getStatus());
-		assertNull(authorInfo.getAlias());
-
-		// check unverified contact
-		checkAuthorInfoContext(txn, remote.getId(), singletonList(contact));
-		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNVERIFIED, authorInfo.getStatus());
-		assertEquals(contact.getAlias(), authorInfo.getAlias());
-
-		// check verified contact
-		Contact verified = getContact(remote, local, true);
-		checkAuthorInfoContext(txn, remote.getId(), singletonList(verified));
-		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(VERIFIED, authorInfo.getStatus());
-		assertEquals(verified.getAlias(), authorInfo.getAlias());
-
-		// check ourselves
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			never(db).getContactsByAuthorId(txn, remote.getId());
-		}});
-
-		authorInfo = contactManager.getAuthorInfo(txn, localAuthor.getId());
-		assertEquals(OURSELVES, authorInfo.getStatus());
-		assertNull(authorInfo.getAlias());
-	}
-
-	private void checkAuthorInfoContext(Transaction txn, AuthorId authorId,
-			Collection<Contact> contacts) throws DbException {
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, authorId);
-			will(returnValue(contacts));
-		}});
-	}
-
 	@Test
 	public void testGetHandshakeLink() throws Exception {
 		Transaction txn = new Transaction(null, true);
@@ -1,5 +1,6 @@
 package org.briarproject.bramble.db;

+import org.briarproject.bramble.api.cleanup.event.CleanupTimerStartedEvent;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.PendingContactId;
@@ -69,6 +70,8 @@ import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonList;
+import static java.util.concurrent.TimeUnit.HOURS;
+import static org.briarproject.bramble.api.db.DatabaseComponent.TIMER_NOT_STARTED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
@@ -510,11 +513,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			throws Exception {
 		context.checking(new Expectations() {{
 			// Check whether the group is in the DB (which it's not)
-			exactly(8).of(database).startTransaction();
+			exactly(10).of(database).startTransaction();
 			will(returnValue(txn));
-			exactly(8).of(database).containsGroup(txn, groupId);
+			exactly(10).of(database).containsGroup(txn, groupId);
 			will(returnValue(false));
-			exactly(8).of(database).abortTransaction(txn);
+			exactly(10).of(database).abortTransaction(txn);
 			// Allow other checks to pass
 			allowing(database).containsContact(txn, contactId);
 			will(returnValue(true));
@@ -523,7 +526,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 				eventExecutor, shutdownManager);

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getGroup(transaction, groupId));
 			fail();
 		} catch (NoSuchGroupException expected) {
@@ -531,7 +534,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getGroupMetadata(transaction, groupId));
 			fail();
 		} catch (NoSuchGroupException expected) {
@@ -539,7 +542,23 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
+					db.getMessageIds(transaction, groupId));
+			fail();
+		} catch (NoSuchGroupException expected) {
+			// Expected
+		}
+
+		try {
+			db.transaction(true, transaction ->
+					db.getMessageIds(transaction, groupId, new Metadata()));
+			fail();
+		} catch (NoSuchGroupException expected) {
+			// Expected
+		}
+
+		try {
+			db.transaction(true, transaction ->
 					db.getMessageMetadata(transaction, groupId));
 			fail();
 		} catch (NoSuchGroupException expected) {
@@ -547,7 +566,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageMetadata(transaction, groupId,
 							new Metadata()));
 			fail();
@@ -556,7 +575,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageStatus(transaction, contactId, groupId));
 			fail();
 		} catch (NoSuchGroupException expected) {
@@ -594,11 +613,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			throws Exception {
 		context.checking(new Expectations() {{
 			// Check whether the message is in the DB (which it's not)
-			exactly(12).of(database).startTransaction();
+			exactly(15).of(database).startTransaction();
 			will(returnValue(txn));
-			exactly(12).of(database).containsMessage(txn, messageId);
+			exactly(15).of(database).containsMessage(txn, messageId);
 			will(returnValue(false));
-			exactly(12).of(database).abortTransaction(txn);
+			exactly(15).of(database).abortTransaction(txn);
 			// Allow other checks to pass
 			allowing(database).containsContact(txn, contactId);
 			will(returnValue(true));
@@ -623,7 +642,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessage(transaction, messageId));
 			fail();
 		} catch (NoSuchMessageException expected) {
@@ -631,7 +650,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageMetadata(transaction, messageId));
 			fail();
 		} catch (NoSuchMessageException expected) {
@@ -639,7 +658,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageState(transaction, messageId));
 			fail();
 		} catch (NoSuchMessageException expected) {
@@ -647,7 +666,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageStatus(transaction, contactId, messageId));
 			fail();
 		} catch (NoSuchMessageException expected) {
@@ -662,6 +681,15 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			// Expected
 		}

+		try {
+			db.transaction(false, transaction ->
+					db.setCleanupTimerDuration(transaction, message.getId(),
+							HOURS.toMillis(1)));
+			fail();
+		} catch (NoSuchMessageException expected) {
+			// Expected
+		}
+
 		try {
 			db.transaction(false, transaction ->
 					db.setMessagePermanent(transaction, message.getId()));
@@ -687,7 +715,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageDependencies(transaction, messageId));
 			fail();
 		} catch (NoSuchMessageException expected) {
@@ -695,12 +723,28 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}

 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageDependents(transaction, messageId));
 			fail();
 		} catch (NoSuchMessageException expected) {
 			// Expected
 		}
+
+		try {
+			db.transaction(false, transaction ->
+					db.startCleanupTimer(transaction, messageId));
+			fail();
+		} catch (NoSuchMessageException expected) {
+			// Expected
+		}
+
+		try {
+			db.transaction(false, transaction ->
+					db.stopCleanupTimer(transaction, messageId));
+			fail();
+		} catch (NoSuchMessageException expected) {
+			// Expected
+		}
 	}

 	@Test
@@ -981,6 +1025,9 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).containsVisibleMessage(txn, contactId, messageId);
 			will(returnValue(true));
 			oneOf(database).raiseSeenFlag(txn, contactId, messageId);
+			will(returnValue(true));
+			oneOf(database).startCleanupTimer(txn, messageId);
+			will(returnValue(TIMER_NOT_STARTED)); // No cleanup duration was set
 			oneOf(database).commitTransaction(txn);
 			oneOf(eventBus).broadcast(with(any(MessagesAckedEvent.class)));
 		}});
@@ -993,6 +1040,56 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		});
 	}

+	@Test
+	public void testReceiveDuplicateAck() throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(database).startTransaction();
+			will(returnValue(txn));
+			oneOf(database).containsContact(txn, contactId);
+			will(returnValue(true));
+			oneOf(database).containsVisibleMessage(txn, contactId, messageId);
+			will(returnValue(true));
+			oneOf(database).raiseSeenFlag(txn, contactId, messageId);
+			will(returnValue(false)); // Already acked
+			oneOf(database).commitTransaction(txn);
+		}});
+		DatabaseComponent db = createDatabaseComponent(database, eventBus,
+				eventExecutor, shutdownManager);
+
+		db.transaction(false, transaction -> {
+			Ack a = new Ack(singletonList(messageId));
+			db.receiveAck(transaction, contactId, a);
+		});
+	}
+
+	@Test
+	public void testReceiveAckWithCleanupTimer() throws Exception {
+		long deadline = System.currentTimeMillis();
+		context.checking(new Expectations() {{
+			oneOf(database).startTransaction();
+			will(returnValue(txn));
+			oneOf(database).containsContact(txn, contactId);
+			will(returnValue(true));
+			oneOf(database).containsVisibleMessage(txn, contactId, messageId);
+			will(returnValue(true));
+			oneOf(database).raiseSeenFlag(txn, contactId, messageId);
+			will(returnValue(true));
+			oneOf(database).startCleanupTimer(txn, messageId);
+			will(returnValue(deadline));
+			oneOf(database).commitTransaction(txn);
+			oneOf(eventBus).broadcast(with(any(
+					CleanupTimerStartedEvent.class)));
+			oneOf(eventBus).broadcast(with(any(MessagesAckedEvent.class)));
+		}});
+		DatabaseComponent db = createDatabaseComponent(database, eventBus,
+				eventExecutor, shutdownManager);
+
+		db.transaction(false, transaction -> {
+			Ack a = new Ack(singletonList(messageId));
+			db.receiveAck(transaction, contactId, a);
+		});
+	}
+
 	@Test
 	public void testReceiveMessage() throws Exception {
 		context.checking(new Expectations() {{
@@ -41,8 +41,12 @@ import org.junit.Test;

 import java.io.File;
 import java.sql.Connection;
+import java.sql.Driver;
+import java.sql.DriverManager;
+import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Enumeration;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -53,10 +57,11 @@ import java.util.concurrent.atomic.AtomicLong;

 import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
-import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
 import static java.util.concurrent.TimeUnit.SECONDS;
+import static org.briarproject.bramble.api.db.DatabaseComponent.NO_CLEANUP_DEADLINE;
+import static org.briarproject.bramble.api.db.DatabaseComponent.TIMER_NOT_STARTED;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
@@ -351,7 +356,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());

 		// Sharing the message should make it sendable
-		db.setMessageShared(txn, messageId);
+		db.setMessageShared(txn, messageId, true);
 		ids = db.getMessagesToSend(txn, contactId, ONE_MEGABYTE, MAX_LATENCY);
 		assertEquals(singletonList(messageId), ids);
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
@@ -631,8 +636,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {

 		// The group should not be visible to the contact
 		assertEquals(INVISIBLE, db.getGroupVisibility(txn, contactId, groupId));
-		assertEquals(emptyMap(),
-				db.getGroupVisibility(txn, groupId));
+		assertTrue(db.getGroupVisibility(txn, groupId).isEmpty());

 		// Make the group visible to the contact
 		db.addGroupVisibility(txn, contactId, groupId, false);
@@ -655,8 +659,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		// Make the group invisible again
 		db.removeGroupVisibility(txn, contactId, groupId);
 		assertEquals(INVISIBLE, db.getGroupVisibility(txn, contactId, groupId));
-		assertEquals(emptyMap(),
-				db.getGroupVisibility(txn, groupId));
+		assertTrue(db.getGroupVisibility(txn, groupId).isEmpty());

 		db.commitTransaction(txn);
 		db.close();
@@ -2040,7 +2043,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertEquals(Long.MAX_VALUE, db.getNextSendTime(txn, contactId));

 		// Share the message - now it should be sendable immediately
-		db.setMessageShared(txn, messageId);
+		db.setMessageShared(txn, messageId, true);
 		assertEquals(0, db.getNextSendTime(txn, contactId));

 		// Mark the message as requested - it should still be sendable
@@ -2347,6 +2350,148 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		db.close();
 	}

+
+	@Test
+	public void testShutdownGracefully() throws Exception {
+		Database<Connection> db = open(false);
+		db.close();
+		open(true);
+		assertFalse(db.wasDirtyOnInitialisation());
+	}
+
+	@Test
+	public void testShutdownDirty() throws Exception {
+		Database<Connection> db = open(false);
+
+		// We want to simulate a dirty shutdown here which would normally be
+		// caused by an empty battery or by force closing the Android app.
+		// As there is no obvious way to simulate this, we're artificially
+		// causing an SqlException during close() here by unloading the JDBC
+		// drivers.
+		List<String> unloadedDrivers = unloadDrivers();
+
+		try {
+			db.close();
+			fail();
+		} catch (Exception e) {
+			// continue
+			e.printStackTrace();
+		}
+
+		// Reloading drivers to continue so that we're able to work with the
+		// database again.
+		reloadDrivers(unloadedDrivers);
+
+		db = open(true);
+		assertTrue(db.wasDirtyOnInitialisation());
+	}
+
+	@Test
+	public void testShutdownDirtyThenGracefully() throws Exception {
+		Database<Connection> db = open(false);
+
+		// Simulating a dirty shutdown here, look at #testShutdownDirty for
+		// details.
+		List<String> unloadedDrivers = unloadDrivers();
+
+		try {
+			db.close();
+			fail();
+		} catch (Exception e) {
+			// continue
+		}
+
+		reloadDrivers(unloadedDrivers);
+
+		db = open(true);
+		assertTrue(db.wasDirtyOnInitialisation());
+
+		db.close();
+		db = open(true);
+		assertFalse(db.wasDirtyOnInitialisation());
+	}
+
+	@Test
+	public void testCleanupTimer() throws Exception {
+		long duration = 60_000;
+		long now = System.currentTimeMillis();
+		AtomicLong time = new AtomicLong(now);
+		Database<Connection> db =
+				open(false, new TestMessageFactory(), new SettableClock(time));
+		Connection txn = db.startTransaction();
+
+		// No messages should be due or scheduled for deletion
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(NO_CLEANUP_DEADLINE, db.getNextCleanupDeadline(txn));
+
+		// Add a group and a message
+		db.addGroup(txn, group);
+		db.addMessage(txn, message, DELIVERED, false, false, null);
+
+		// No messages should be due or scheduled for deletion
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(NO_CLEANUP_DEADLINE, db.getNextCleanupDeadline(txn));
+
+		// Set the message's cleanup timer duration
+		db.setCleanupTimerDuration(txn, messageId, duration);
+
+		// No messages should be due or scheduled for deletion
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(NO_CLEANUP_DEADLINE, db.getNextCleanupDeadline(txn));
+
+		// Start the message's cleanup timer
+		assertEquals(now + duration, db.startCleanupTimer(txn, messageId));
+
+		// The timer can't be started again
+		assertEquals(TIMER_NOT_STARTED, db.startCleanupTimer(txn, messageId));
+
+		// No messages should be due for deletion, but the message should be
+		// scheduled for deletion
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(now + duration, db.getNextCleanupDeadline(txn));
+
+		// Stop the timer
+		db.stopCleanupTimer(txn, messageId);
+
+		// No messages should be due or scheduled for deletion
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(NO_CLEANUP_DEADLINE, db.getNextCleanupDeadline(txn));
+
+		// Start the timer again
+		assertEquals(now + duration, db.startCleanupTimer(txn, messageId));
+
+		// No messages should be due for deletion, but the message should be
+		// scheduled for deletion
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(now + duration, db.getNextCleanupDeadline(txn));
+
+		// 1 ms before the timer expires, no messages should be due for
+		// deletion but the message should be scheduled for deletion
+		time.set(now + duration - 1);
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(now + duration, db.getNextCleanupDeadline(txn));
+
+		// When the timer expires, the message should be due and scheduled for
+		// deletion
+		time.set(now + duration);
+		assertEquals(singletonMap(groupId, singletonList(messageId)),
+				db.getMessagesToDelete(txn));
+		assertEquals(now + duration, db.getNextCleanupDeadline(txn));
+
+		// 1 ms after the timer expires, the message should be due and
+		// scheduled for deletion
+		time.set(now + duration + 1);
+		assertEquals(singletonMap(groupId, singletonList(messageId)),
+				db.getMessagesToDelete(txn));
+		assertEquals(now + duration, db.getNextCleanupDeadline(txn));
+
+		// Once the message has been deleted, it should no longer be due
+		// or scheduled for deletion
+		db.deleteMessage(txn, messageId);
+		assertTrue(db.getMessagesToDelete(txn).isEmpty());
+		assertEquals(NO_CLEANUP_DEADLINE, db.getNextCleanupDeadline(txn));
+	}
+
 	private Database<Connection> open(boolean resume) throws Exception {
 		return open(resume, new TestMessageFactory(), new SystemClock());
 	}
@@ -2402,6 +2547,31 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 				rootKey, alice);
 	}

+	private List<String> unloadDrivers() {
+		Enumeration<Driver> drivers = DriverManager.getDrivers();
+		List<String> unloaded = new ArrayList<>();
+		while (drivers.hasMoreElements()) {
+			Driver d = drivers.nextElement();
+			try {
+				DriverManager.deregisterDriver(d);
+				unloaded.add(d.getClass().getName());
+			} catch (SQLException e) {
+				e.printStackTrace();
+				fail();
+			}
+		}
+		return unloaded;
+	}
+
+	private void reloadDrivers(List<String> unloadedDrivers)
+			throws ClassNotFoundException, IllegalAccessException,
+			InstantiationException, SQLException {
+		for (String driverName : unloadedDrivers) {
+			DriverManager.registerDriver(
+					(Driver) Class.forName(driverName).newInstance());
+		}
+	}
+
 	@After
 	public void tearDown() {
 		deleteTestDirectory(testDir);
@@ -27,6 +27,7 @@ import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedE
 import org.briarproject.bramble.api.rendezvous.event.RendezvousPollEvent;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.CaptureArgumentAction;
 import org.briarproject.bramble.test.DbExpectations;
@@ -79,6 +80,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			context.mock(KeyMaterialSource.class);
 	private final RendezvousEndpoint rendezvousEndpoint =
 			context.mock(RendezvousEndpoint.class);
+	private final Cancellable cancellable = context.mock(Cancellable.class);

 	private final Executor ioExecutor = new ImmediateExecutor();
 	private final PendingContact pendingContact = getPendingContact();
@@ -107,7 +109,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		long beforeExpiry = pendingContact.getTimestamp()
 				+ RENDEZVOUS_TIMEOUT_MS - 1000;
 		long afterExpiry = beforeExpiry + POLLING_INTERVAL_MS;
-		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();
+		AtomicReference<Runnable> capturePollTask;

 		// Start the service
 		context.checking(new DbExpectations() {{
@@ -121,21 +123,17 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == OFFLINE)));
-			// Capture the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});

 		expectDeriveRendezvousKey();
+		capturePollTask = expectSchedulePolling();

 		rendezvousPoller.startService();
 		context.assertIsSatisfied();

-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();

 		capturePollTask.get().run();
 	}
@@ -157,10 +155,6 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == FAILED)));
-			// Schedule the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
 		}});

 		rendezvousPoller.startService();
@@ -183,7 +177,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
 		context.assertIsSatisfied();

-		// Add the pending contact - endpoint should be created and polled
+		// Add the pending contact - endpoint should be created and polled,
+		// polling should be scheduled
 		expectAddPendingContact(beforeExpiry, WAITING_FOR_CONNECTION);
 		expectDeriveRendezvousKey();
 		expectCreateEndpoint();
@@ -200,12 +195,16 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 					any(ConnectionHandler.class)))));
 		}});

+		expectSchedulePolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();

-		// Remove the pending contact - endpoint should be closed
+		// Remove the pending contact - endpoint should be closed,
+		// polling should be cancelled
 		expectCloseEndpoint();
+		expectCancelPolling();

 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
@@ -221,10 +220,10 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		long beforeExpiry = pendingContact.getTimestamp()
 				+ RENDEZVOUS_TIMEOUT_MS - 1000;
 		long afterExpiry = beforeExpiry + POLLING_INTERVAL_MS;
+		AtomicReference<Runnable> capturePollTask;

-		// Start the service, capturing the poll task
-		AtomicReference<Runnable> capturePollTask =
-				expectStartupWithNoPendingContacts();
+		// Start the service
+		expectStartupWithNoPendingContacts();

 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
@@ -235,7 +234,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
 		context.assertIsSatisfied();

-		// Add the pending contact - endpoint should be created and polled
+		// Add the pending contact - endpoint should be created and polled,
+		// polling should be scheduled
 		expectAddPendingContact(beforeExpiry, WAITING_FOR_CONNECTION);
 		expectDeriveRendezvousKey();
 		expectCreateEndpoint();
@@ -252,13 +252,17 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 					any(ConnectionHandler.class)))));
 		}});

+		capturePollTask = expectSchedulePolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();

-		// Run the poll task - pending contact expires, endpoint is closed
+		// Run the poll task - pending contact expires, endpoint is closed,
+		// polling is cancelled
 		expectPendingContactExpires(afterExpiry);
 		expectCloseEndpoint();
+		expectCancelPolling();

 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -286,6 +290,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		// Add the pending contact - no endpoints should be created yet
 		expectAddPendingContact(beforeExpiry, OFFLINE);
 		expectDeriveRendezvousKey();
+		expectSchedulePolling();

 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
@@ -307,6 +312,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		context.assertIsSatisfied();

 		// Remove the pending contact - endpoint is already closed
+		expectCancelPolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
 	}
@@ -348,8 +355,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();

-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();

 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -385,8 +393,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new RendezvousConnectionOpenedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();

-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();

 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -417,8 +426,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new RendezvousConnectionOpenedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();

-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();

 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -447,6 +457,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		context.assertIsSatisfied();

 		// Pending contact is removed - no event should be broadcast
+		expectCancelPolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
@@ -456,25 +468,35 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				pendingContact.getId(), false));
 	}

-	private AtomicReference<Runnable> expectStartupWithNoPendingContacts()
-			throws Exception {
-		Transaction txn = new Transaction(null, true);
+	private AtomicReference<Runnable> expectSchedulePolling() {
 		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();

+		context.checking(new Expectations() {{
+			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
+					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
+					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
+			will(doAll(new CaptureArgumentAction<>(capturePollTask,
+					Runnable.class, 0), returnValue(cancellable)));
+		}});
+
+		return capturePollTask;
+	}
+
+	private void expectCancelPolling() {
+		context.checking(new Expectations() {{
+			oneOf(cancellable).cancel();
+		}});
+	}
+
+	private void expectStartupWithNoPendingContacts() throws Exception {
+		Transaction txn = new Transaction(null, true);
+
 		context.checking(new DbExpectations() {{
 			// Load the pending contacts
 			oneOf(db).transaction(with(true), withDbRunnable(txn));
 			oneOf(db).getPendingContacts(txn);
 			will(returnValue(emptyList()));
-			// Capture the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});
-
-		return capturePollTask;
 	}

 	private void expectAddPendingContact(long now,
@@ -530,7 +552,6 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 	private AtomicReference<Runnable> expectStartupWithPendingContact(long now)
 			throws Exception {
 		Transaction txn = new Transaction(null, true);
-		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();

 		context.checking(new DbExpectations() {{
 			// Load the pending contacts
@@ -543,17 +564,10 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == OFFLINE)));
-			// Capture the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});

 		expectDeriveRendezvousKey();
-
-		return capturePollTask;
+		return expectSchedulePolling();
 	}

 	private void expectPendingContactExpires(long now) {
@@ -0,0 +1,122 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
+
+import java.util.Queue;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executor;
+import java.util.concurrent.PriorityBlockingQueue;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static org.junit.Assert.fail;
+
+/**
+ * A {@link TaskScheduler} for use in tests. The scheduler keeps all scheduled
+ * tasks in a queue until {@link #runTasks()} is called.
+ */
+@NotNullByDefault
+class TestTaskScheduler implements TaskScheduler {
+
+	private final Queue<Task> queue = new PriorityBlockingQueue<>();
+	private final Clock clock;
+
+	TestTaskScheduler(Clock clock) {
+		this.clock = clock;
+	}
+
+	@Override
+	public Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return schedule(task, executor, delay, unit, cancelled);
+	}
+
+	@Override
+	public Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return scheduleWithFixedDelay(task, executor, delay, interval, unit,
+				cancelled);
+	}
+
+	private Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit, AtomicBoolean cancelled) {
+		long delayMillis = MILLISECONDS.convert(delay, unit);
+		long dueMillis = clock.currentTimeMillis() + delayMillis;
+		Task t = new Task(task, executor, dueMillis, cancelled);
+		queue.add(t);
+		return t;
+	}
+
+	private Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit, AtomicBoolean cancelled) {
+		// All executions of this periodic task share a cancelled flag
+		Runnable wrapped = () -> {
+			task.run();
+			scheduleWithFixedDelay(task, executor, interval, interval, unit,
+					cancelled);
+		};
+		return schedule(wrapped, executor, delay, unit, cancelled);
+	}
+
+	/**
+	 * Runs any scheduled tasks that are due.
+	 */
+	void runTasks() throws InterruptedException {
+		long now = clock.currentTimeMillis();
+		while (true) {
+			Task t = queue.peek();
+			if (t == null || t.dueMillis > now) return;
+			t = queue.poll();
+			// Submit the task to its executor and wait for it to finish
+			if (!t.run().await(1, MINUTES)) fail();
+		}
+	}
+
+	private static class Task
+			implements Cancellable, Comparable<Task> {
+
+		private final Runnable task;
+		private final Executor executor;
+		private final long dueMillis;
+		private final AtomicBoolean cancelled;
+
+		private Task(Runnable task, Executor executor, long dueMillis,
+				AtomicBoolean cancelled) {
+			this.task = task;
+			this.executor = executor;
+			this.dueMillis = dueMillis;
+			this.cancelled = cancelled;
+		}
+
+		@SuppressWarnings("UseCompareMethod") // Animal Sniffer
+		@Override
+		public int compareTo(Task task) {
+			return Long.valueOf(dueMillis).compareTo(task.dueMillis);
+		}
+
+		/**
+		 * Submits the task to its executor and returns a latch that will be
+		 * released when the task finishes.
+		 */
+		public CountDownLatch run() {
+			if (cancelled.get()) return new CountDownLatch(0);
+			CountDownLatch latch = new CountDownLatch(1);
+			executor.execute(() -> {
+				task.run();
+				latch.countDown();
+			});
+			return latch;
+		}
+
+		@Override
+		public void cancel() {
+			cancelled.set(true);
+		}
+	}
+}
@@ -0,0 +1,98 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.test.SettableClock;
+import org.briarproject.bramble.test.TimeTravel;
+
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.atomic.AtomicLong;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class TimeTravelModule {
+
+	public static class EagerSingletons {
+		@Inject
+		TaskScheduler scheduler;
+	}
+
+	private final ScheduledExecutorService scheduledExecutorService;
+	private final Clock clock;
+	private final TaskScheduler taskScheduler;
+	private final TimeTravel timeTravel;
+
+	public TimeTravelModule() {
+		this(false);
+	}
+
+	public TimeTravelModule(boolean travel) {
+		// Discard tasks that are submitted during shutdown
+		RejectedExecutionHandler policy =
+				new ScheduledThreadPoolExecutor.DiscardPolicy();
+		scheduledExecutorService =
+				new ScheduledThreadPoolExecutor(1, policy);
+		if (travel) {
+			// Use a SettableClock and TestTaskScheduler to allow time travel
+			AtomicLong time = new AtomicLong(System.currentTimeMillis());
+			clock = new SettableClock(time);
+			TestTaskScheduler testTaskScheduler = new TestTaskScheduler(clock);
+			taskScheduler = testTaskScheduler;
+			timeTravel = new TimeTravel() {
+				@Override
+				public void setCurrentTimeMillis(long now)
+						throws InterruptedException {
+					time.set(now);
+					testTaskScheduler.runTasks();
+				}
+
+				@Override
+				public void addCurrentTimeMillis(long add)
+						throws InterruptedException {
+					time.addAndGet(add);
+					testTaskScheduler.runTasks();
+				}
+			};
+		} else {
+			// Use the default clock and task scheduler
+			clock = new SystemClock();
+			taskScheduler = new TaskSchedulerImpl(scheduledExecutorService);
+			timeTravel = new TimeTravel() {
+				@Override
+				public void setCurrentTimeMillis(long now) {
+					throw new UnsupportedOperationException();
+				}
+
+				@Override
+				public void addCurrentTimeMillis(long add) {
+					throw new UnsupportedOperationException();
+				}
+			};
+		}
+	}
+
+	@Provides
+	Clock provideClock() {
+		return clock;
+	}
+
+	@Provides
+	@Singleton
+	TaskScheduler provideTaskScheduler(LifecycleManager lifecycleManager) {
+		lifecycleManager.registerForShutdown(scheduledExecutorService);
+		return taskScheduler;
+	}
+
+	@Provides
+	TimeTravel provideTimeTravel() {
+		return timeTravel;
+	}
+}
@@ -3,8 +3,8 @@ package org.briarproject.bramble.test;
 import org.briarproject.bramble.api.FeatureFlags;
 import org.briarproject.bramble.battery.DefaultBatteryManagerModule;
 import org.briarproject.bramble.event.DefaultEventExecutorModule;
-import org.briarproject.bramble.system.DefaultTaskSchedulerModule;
 import org.briarproject.bramble.system.DefaultWakefulIoExecutorModule;
+import org.briarproject.bramble.system.TimeTravelModule;

 import dagger.Module;
 import dagger.Provides;
@@ -12,16 +12,37 @@ import dagger.Provides;
@Module(includes = {
 		DefaultBatteryManagerModule.class,
 		DefaultEventExecutorModule.class,
-		DefaultTaskSchedulerModule.class,
 		DefaultWakefulIoExecutorModule.class,
 		TestDatabaseConfigModule.class,
 		TestPluginConfigModule.class,
-		TestSecureRandomModule.class
+		TestSecureRandomModule.class,
+		TimeTravelModule.class
 })
 public class BrambleCoreIntegrationTestModule {

 	@Provides
 	FeatureFlags provideFeatureFlags() {
-		return () -> true;
+		return new FeatureFlags() {
+
+			@Override
+			public boolean shouldEnableImageAttachments() {
+				return true;
+			}
+
+			@Override
+			public boolean shouldEnableProfilePictures() {
+				return true;
+			}
+
+			@Override
+			public boolean shouldEnableDisappearingMessages() {
+				return true;
+			}
+
+			@Override
+			public boolean shouldEnableConnectViaBluetooth() {
+				return true;
+			}
+		};
 	}
 }
@@ -38,7 +38,6 @@ import static org.briarproject.bramble.test.TestUtils.getContact;
 import static org.briarproject.bramble.test.TestUtils.getGroup;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
-import static org.briarproject.bramble.versioning.ClientVersioningConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_LOCAL;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_UPDATE_VERSION;
 import static org.junit.Assert.assertEquals;
@@ -60,8 +59,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 	private final ClientId clientId = getClientId();
 	private final long now = System.currentTimeMillis();
 	private final Transaction txn = new Transaction(null, false);
-	private final BdfDictionary groupMeta = BdfDictionary.of(
-			new BdfEntry(GROUP_KEY_CONTACT_ID, contact.getId().getInt()));

 	private ClientVersioningManagerImpl createInstance() {
 		context.checking(new Expectations() {{
@@ -123,8 +120,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(db).addGroup(txn, contactGroup);
 			oneOf(db).setGroupVisibility(txn, contact.getId(),
 					contactGroup.getId(), SHARED);
-			oneOf(clientHelper).mergeGroupMetadata(txn, contactGroup.getId(),
-					groupMeta);
+			oneOf(clientHelper).setContactId(txn, contactGroup.getId(),
+					contact.getId());
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(clientHelper).createMessage(contactGroup.getId(), now,
@@ -460,9 +457,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(db).deleteMessage(txn, oldRemoteUpdateId);
 			oneOf(db).deleteMessageMetadata(txn, oldRemoteUpdateId);
 			// Get contact ID
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			// No states or visibilities have changed
 		}});

@@ -492,10 +488,9 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			// Load the latest local update
 			oneOf(clientHelper).getMessageAsList(txn, oldLocalUpdateId);
 			will(returnValue(oldLocalUpdateBody));
-			// Get client ID
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			// Get contact ID
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			// No states or visibilities have changed
 		}});

@@ -546,8 +541,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		BdfDictionary newLocalUpdateMeta = BdfDictionary.of(
 				new BdfEntry(MSG_KEY_UPDATE_VERSION, 2L),
 				new BdfEntry(MSG_KEY_LOCAL, true));
-		BdfDictionary groupMeta = BdfDictionary.of(
-				new BdfEntry(GROUP_KEY_CONTACT_ID, contact.getId().getInt()));

 		context.checking(new Expectations() {{
 			oneOf(clientHelper).toList(newRemoteUpdate);
@@ -577,9 +570,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).addLocalMessage(txn, newLocalUpdate,
 					newLocalUpdateMeta, true, false);
 			// The client's visibility has changed
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			oneOf(db).getContact(txn, contact.getId());
 			will(returnValue(contact));
 			oneOf(hook).onClientVisibilityChanging(txn, contact, visibility);
@@ -619,8 +611,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		BdfDictionary newLocalUpdateMeta = BdfDictionary.of(
 				new BdfEntry(MSG_KEY_UPDATE_VERSION, 2L),
 				new BdfEntry(MSG_KEY_LOCAL, true));
-		BdfDictionary groupMeta = BdfDictionary.of(
-				new BdfEntry(GROUP_KEY_CONTACT_ID, contact.getId().getInt()));

 		context.checking(new Expectations() {{
 			oneOf(clientHelper).toList(newRemoteUpdate);
@@ -650,9 +640,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).addLocalMessage(txn, newLocalUpdate,
 					newLocalUpdateMeta, true, false);
 			// The client's visibility has changed
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			oneOf(db).getContact(txn, contact.getId());
 			will(returnValue(contact));
 			oneOf(hook).onClientVisibilityChanging(txn, contact, INVISIBLE);
@@ -16,8 +16,8 @@ dependencies {
 	implementation fileTree(dir: 'libs', include: '*.jar')
 	implementation 'net.java.dev.jna:jna:4.5.2'
 	implementation 'net.java.dev.jna:jna-platform:4.5.2'
-	tor 'org.briarproject:tor:0.3.5.10@zip'
-	tor 'org.briarproject:obfs4proxy:0.0.7@zip'
+	tor 'org.briarproject:tor:0.3.5.13-1@zip'
+	tor 'org.briarproject:obfs4proxy:0.0.12-dev-40245c4a@zip'

 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'

--- a/Show More
+++ b/Show More